’66 D-REVERB 22W · Solder Monster #3000 Guitar Tech Screwdriver Set #1606 Wire Stripper #1607 Wire Cutter #0501 Solomon SL-30 Soldering Station #1609 Round Nose Bending Pliers

A S S E M B LY I N S T R U C T I O N SWith loads of helpful tips!

Famously clean withenough guts to gig!

’66 D-REVERB 22W C O M B O A M P K I T ORIGINAL AB763 CIRCUIT

stewmac.com 2 © 2019 StewMac

Contents

About this iconic amp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Parts list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Tools and supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Amp voltages are seriously dangerous! . . . . . . . . . . . . . . . . . . . . . . . . . . 6

How to use a snuffer stick . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

How to read resistor values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Capacitor values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Prepping the cabinet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Prepping the eyelet boards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Tips for great soldering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Installing the chassis-mounted components . . . . . . . . . . . . . . . . . . . 13

How to install parts on an eyelet board in three steps . . . . . . . . . . 22

Wrapping parts onto the bias board . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Wrapping parts onto the filter cap board . . . . . . . . . . . . . . . . . . . . . . . 25

Wrapping parts onto the main eyelet board . . . . . . . . . . . . . . . . . . . . 27

Installing parts and preparing for testing . . . . . . . . . . . . . . . . . . . . . . 52

Testing and troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Final assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Tips for using the 66D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Learning more: secrets revealed in the schematic . . . . . . . . . . . . . . 58

Circuit schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

More iconic amp kits from StewMac . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Complete wiring diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Tube replacement chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

COPYRIGHT WARNINGThis material is protected by copyright and has been created by and solely for the purposes of StewMac . You may not sell, alter or further reproduce any part of this material, or distribute it to any other per-son . Where provided to you in electronic format, you may only print from it for your own private use . Failure to comply with the terms of this warning exposes you to legal action for copyright infringement .

How to build this kit!


’66 D-REVERB 22W COMBO AMP KIT ORIGINAL AB763 CIRCUIT

For many players, this is the #1 desert island amp!

Be excited!Your new StewMac ’66 D-Reverb will be a blast to play through and even more fun to build .

Perfect for recording as well as performing, the D-Reverb produces stinging clarity that absolutely refuses to get lost in the mix .

This amp is an ICONOne of the most popular designs ever, this amp lives in the happy middle between bright clarity and rich distortion . It excels in the studio and on the stage . While capable of crystal clear tones at good volume, you can push this one into beautifully saturated, play-sensitive distortion .

It’s all here: clarity, distortion, and rectifier tube sag .

StewMac ICON KITS bring classics that are no longer made, or are simply unaffordable, within reach . And the best part is you get to build them with your own hands .

We give painstaking attention to parts selection, authentic materials, and instantly recognizable details—everything that makes the originals so sought after .

Build it with StewMacThese immersive instructions walk you through every step of creating your ’66 D-Reverb . And you’ll learn a lot, gaining a deep knowledge of your amp’s inner workings .

Follow our steps closely for safety, too: we’ve carefully laid out a path that even newcomers can follow in handling electrical components .

Building an amp can seem daunting, but nobody makes it easier than StewMac . Watch for helpful tips along the way, too—we’re here to help!

Let’s get building!


Here’s how to build this amp!

Wiring goes like this:1. First, you’ll wrap the leads, connecting them without solder. 2. Then double-check all the connections. Don’t rush!3. When everything checks out, it's time to solder. The numbered steps tell you when.

Get the cabinet ready, starting at Step 1 on page 8.You’ll prep the metal chassis and the eyelet board too.

Learn more:You don’t need to read the schematic, but it’s fun! See how your guitar’s signal gets processed into sound on page 59.

Sort your components by type, using the parts list.Quick look:

See page 11

#10733 © 2018 StewMac

GroundJackTransformer Preamp tube

plategrid

cathode

Power tube

grid

plate

cathode

screen

Capacitor

Electrolytic Cap.

DiodeResistor Potentiometers Rectifier tube Optoisolater

plate cathode

filamentplate

Shieldedcable

’66 D-REVERB 22WORIGINAL AB763 CIRCUIT

Gain GainProcessing

Processing

Processing

Output

Power

Negative Feedback

68K

25μF

50V

25μF

50V

25μF

50V

1.5K

6.8K

68K

B

B D

2

2

6+180V

6+180V

+1.3V 8

+1.3V 8

8+1.3V

+200V

1

+77V

250pF

10p

F

.1p

F

.01μ

F

.047μF

.022μF

.0033μF

.01μF

AE

C

BC

VIBRATOPEDAL

REVERBPEDAL

REVERB UNITOutputInput

.1μF .01μF

.1μF

.1μF

SOCKET V1

7025 SOCKET V4

7025

NO

RM

AL

SOCKET V3

12AT7

SOCKET V9

GZ34

SOCKET V5

12AX7

SOCKET V6

12AT7

SOCKET V7

6V6GT

SOCKET V8

6V6GT

.1μF

500pF

.047μF1 10

0K

100K

100K

100Ω

100Ω

82K

220K

220K

220K

47Ω

1M1M

100K

3.3M

220K

22K

1.5K

470Ω

820Ω

470Ω

470Ω1.5K

10K10K

100K

220K

100K

100K

100K

100K

100K

470K

220K

2.2M 22

0K

10M

10K

470Ω

250K

ATR

EBLE

1 MA

VO

LUM

E

250K

AB

ASS

3MRASPEED

50KR

AIN

TEN

SITY

68K

25μF

50V

1.5K

25μF

50V

820Ω

6.8K

68K

1M1M

2

2

+170V 1

+180V 1

3 +1.3V

3 +1.3V

+170V6

+180V6

250pF 47pF

A

.1μF

SOCKET V2

7025

VIB

RA

TO

.047μF1

100K

250K

ATR

EBLE

100K

LR

EVER

B

1 MA

VO

LUM

E

250K

AB

ASS

7 EXTENSIONSPEAKER

TR3

TR2

STANDBYSWITCH

TR4

TR1

TR1: 125P33A 125P23B TR2: 125C3ATR3: 125A1ATR4: 125A20B

8

8

5

6 8

4 2

3 +1.2V

+170V11

2 2

+410V

6

8 +8.7V

3 +370V

3 +415V

-35V

+41

5V

2.2K

1M

330VACAC switch

1 ampslow-blow fuse

To tube heaters and pilot light

330VAC

820Ω

25μF

50V

16μF

450V

16μF

450V

25μF

50V

27K

25μF

50V

100A

K

.02μ

F

16μF

450V

16μF

450V

D 16μF

450V

1M

1M10KL

2 1

3

6

7

8

7

7

2

8

5

4 +365V

4 +415V

OutputGain Processing


Resistors

r (1) 47Ω .5W carbon composite




r (4) 1.5K .5W carbon composite




r (1) 10K .5W carbon composite






r (12)100K .5W carbon composite



r (7) 1M .5W carbon composite

r (1) 2.2M .5W carbon composite

r (1) 3.3M .5W carbon composite

r (3) 470Ω 1W carbon film

r (1) 10M 1W carbon film

r (2) 10K 2W metal oxide

Yellow Violet Black Gold

Brown Black Brown Gold

Yellow Violet Brown Gold

Brown Green Red Gold

Gray Red Brown Gold

Red Red Red Gold

Red Violet Orange Gold

Red Violet Red Gold

Blue Gray Red Gold

Red Red Green Gold

Orange Orange Green Gold

Red Red Orange Gold

Green Blue Orange Gold

Blue Gray Orange Gold

Gray Red Orange Gold

Brown Black Yellow Gold

Brown Black Orange Gold

Red Red Yellow Gold

Yellow Violet Yellow Gold

Brown Black Green Gold

Yellow Violet Brown Gold

Brown Black Blue Gold

Brown Black Orange Gold

Capacitors

r (1) 47pF 500V silver mica



r (1) 10pF 500V ceramic disk

r (2) .01μF 500V ceramic disk

r (1) .02μF 500V ceramic disk

r (1) .001μF 600V Orange Drop





r (5) 16μF 500V electrolytic

r (8) 25μF 50V sprague atom

Diode, optoisolator

r (1) 1N4007 1000V rectifier diode

r (1) Optoisolator

250

102J 1119

+

25µF

510+47

332J 600V

223J 600V

473J 600V

104J 600V

16μF

103K

203Z

r (1) Cabinet

r (1) Chassis

r (1) Capacitor pan

r (3) Eyelet boards

r (3) Insulator boards

r (1) Faceplate/backplate set

r (1) 12” speaker

Hardware

r (6) 8-32 machine screw, 3/8"r (10) 8-32 locknut

r (4) 6-32 machine screw, 1/2"r (4) 6-32 locknut

r (6) 4-40 machine screw, 3/8"r (20) 4-40 machine screw, 1/4"r (26) 4-40 locknut

r (4) Self-tapping screw

r (1) Black wood screw

r (1) Power cord clamp

r (1) Strain relief for power cord

r (6) Rubber grommet

r (2) Chassis mounting strapr (4) Chassis strap screw and nut

Parts list


12AX

712AT7

6V6

5AR

4

4

3 2

18

76

5

6

4 3 21

987

5

Tubes, lamps, fuses, and sockets

r (4) RCA-style jack

r (1) Two-lug jack

r (5) Three-lug jack

r (6) Nine-pin tube socket

r (6) Shield for nine-pin tube socket

r (3) Eight-pin tube socket

r (3) Tension clip for eight-pin socket

r (4) 12AX7 preamp tube (also called ECC83S)

r (2) 12AT7 preamp tube (also called ECC81)

r (2) 6V6S power tube

r (1) 5AR4 rectifier tube (also called GZ34)

r (1) Fuse socket

r (1) Fuse (1 amp, slow blow)

r (1) Pilot lamp socket with lens

r (1) Pilot lamp bulb (#47)

Control pots and more

r (1) 10KL bias pot

r (1) 100KL control pot

r (4) 250KA control pot

r (2) 1MA control pot

r (1) 3MRA control pot

r (1) 50KRA control pot

r (9) Knob

r (2) Three-lug grounding strip

r (2) Power switch (2 lugs)

r (1) Ground switch (3 lugs)

r (1) Power cord

r (1) Speaker plug

Transformers

r (1) Power transformer

r (1) Output transformer

r (1) Reverb driver

r (1) Filter choke

Reverb

r (1) Reverb tank

r (1) Reverb tank bag

r (1) Reverb wiring kit

r (1) Footswitch

10

0KL

25

0KA

1MA

3MRA

50

KRA

1234

10

56

7 8 9

10KL

Wire

r (1) Heater wires (pre-tinned)

r (1) Speaker wires (multi-strand)

r (1) Yellow push-back wire

r (1) Green push-back wire

Heat-shrink tubing

r (2) 1/8" diameter

Vintage-style push-back wire lets you push the insulation back instead of trimming it. BUT: Trimming it still works better!

Parts list


#0531 StewMac Solder Monster

#3000 Guitar Tech Screwdriver Set

#1606 Wire Stripper

#1607 Wire Cutter

#0501 Solomon SL-30 Soldering Station

#1609 Round Nose Bending Pliers #0505

Kester Pocket-Pak Solder

StewMac’s Solder Monster holds parts while you solder

Tools and supplies

Required Phillips screwdrivers, #1 and #2 Item #3000 Guitar Tech Screwdriver Set

Needle nose pliers Item #1610 Long Nose Pliers

Wire cutter Item #1607 Wire Cutter

Wire stripper Item #1606 Wire Stripper

Soldering iron (preferably 40W) Item #0501 Solomon SL-30 Soldering Station

Solder (at least one Pocket-Pak) Item #0505 Kester Pocket-Pak Solder

Solder sucker Item #0503 Solomon Solder Sucker

Drill with a 5/32", 5/64", and 1/4" bit For mounting eyelet board and filter cap

Ruler Item #4905 StewMac Shop Rule

Digital multimeter Item #3618 Fieldpiece Pocket Multimeter

Snuffer stick (bleed resistor) Item #1552 Snuffer Stick

Pencil Wooden chopsticks Glue Wood glue, white glue, or contact cement for gluing a paper label inside the cabinet

Butane lighter or matches For heating heat-shrink tubing

Helpful Round nose bending pliers Item #1609 Round Nose Bending Pliers

Solder wick Item #0504 Solder Wick, 5-foot roll

Soldering aids Item #0521 StewMac Soldering Aids

Soldering stand Item #0506 Solomon Soldering Stand

Solder Monster, or helping hand tool Item #0531 StewMac Solder Monster

Chassis stand Item #10750 Chassis Stand

Printed circuit board vise Scratch awl or center punch Item #3000 Guitar Tech Screwdriver Set

Tray for loose parts Bias meter for accurate biasing Item #1580 VHT Tube Tester + Amp Bias Meter


High voltage, even when unpluggedWhen you turn on an amp, the capacitors are designed to take on a charge and hold it . That stored voltage is enough to injure you seriously, or even kill you .

These components aren’t a threat until the first time you plug the amp in . The stored electricity can be safely discharged to ground with a snuffer stick . See how to use it below .

Once your amp has been turned on, don’t touch the wiring with your bare hands—even after turning it off . If you need to press on a contact, use a chopstick or Sharpie marker, which are both non-conductive . Don’t use a pencil, because graphite is conductive .

It’s important that you understand the dangers so you’re working safely . Here’s how to do it right .

Wear rubber-soled shoesRubber soles increase the insulation between yourself and the ground .

Take off your ringA metal ring on your finger can bridge a hot connection to ground .

Wear safety glassesRosin-core solder sometimes bubbles up, and it can spew molten specks into the air . You don’t want molten solder in your eyes .

It’s better not to work aloneElectrical shocks can incapacitate you, and having someone available to call 911 can be a lifesaver .

How to use a snuffer stickTo discharge a capacitor, clip the snuffer stick lead to ground—preferably a mounting bolt on the power transformer . Hold the tip of the stick to the cap’s positive lead and use your multimeter to watch the voltage drain to less than 18V .

Take breaks and stop when you’re tiredFatigue leads to mistakes, and no one can afford mistakes when working with electricity .

Stay suspiciousWhether it’s the first time you’ve been inside a live ampli-fier or the 100th time, don’t become complacent . If you discharge the caps and walk away for a few minutes, check again for residual voltage when you return . Capacitors can self-charge through a phenomenon known as dielectric memory .

Check before powering on It’s easy to forget that you a left a stray tool or wire in the chassis . It’s also easy to forget to re-attach the speaker wire, and that can fry an output transformer in seconds . Constant vigilance is your friend when working on amps .

Always unplug itUnplug the amp whenever you don’t specifically need it plugged in . Some points are always hot when the amp’s plugged in, even if the power switch is off . These points include the lugs on the fuse socket, power switch, and standby switch .

Amp voltages are seriously dangerous!

Professionals who work on amps take these safety habits very seriously


A resistor’s value—the amount of resistance it creates—is rated in ohms (Ω) . Larger ohm values mean more resistance . For example, a 100Ω resistor creates ten times as much re-sistance as a 10Ω resistor .

The resistors used in amplifiers are too small to have value numbers printed on them . Instead, a system of colored bands tells their values . The key to reading these bands is provided below . However, an easier way to decode these bands is to download one of the many smartphone apps for this purpose .

One band will be the nearest to an end of the resistor . That band tells the first value . Combine it with the value of band 2 to get a two-digit number (68 in our example below) . Multiply that number by band 3 (68 x 1,000 = 68,000) . Thou-sands are represented by the letter K, so this resistor is 68K (kilo-ohms, or KΩ) .

If there is a fourth band, it will be either silver or gold . This indicates the tolerance allowed during manufacturing . The resistors used in this kit have a +/- 5% tolerance, represented by a gold band 4 .

A magnifying glass helps a lot . The bands on a 470Ω resistor are yellow/violet/brown, and the bands on a 47K resistor are yellow/violet/orange . They’re easily confused!

Can’t read the colors?You can always use a multimeter to test a resistor’s value . Set your meter to ohms and connect the test leads on each side of the resistor .

Capacitor values are typically printed on the component . The key values with caps are their capacitance and voltage .

Think of a capacitor as a container that can hold electricity . Capacitance, measured in farads, refers to how much elec-tricity this container can hold—its capacity . One farad (1F) would be much too large for use in an amplifier . Caps for amps are rated in millionths of a farad, called microfarads (μF), or trillionths of a farad: picofarads (pF) . The voltage spec for a cap refers to how much DC voltage it can handle at any given time .

A unique property of capacitors is that they don’t allow DC current to flow past them, only AC current . This is important in parts of an amplifier circuit, such as the path between a preamp stage and a power amp stage . Here, a “coupling capacitor" will block DC voltage, allowing only the AC guitar signal to pass .

Filter capsCapacitors also filter out 60Hz hum, or “ripple," after the AC current from the wall is converted to DC . These capacitors are called filter caps, because they filter out the ripple from a power supply . The filter caps in this amp are the 16μF electrolytic capacitors .

Electrolytic capsElectrolytic capacitors contain electrolyte: a liquid or gel that gives them a large storage capacity . Electrolytic caps are typically polarized .

Polarized capsSome capacitors have polarity and some don’t . It’s extremely important to install polarized caps correctly in a circuit . The positive lead of an electrolytic cap will be indicated by an indented ring around one edge of the capacitor . The nega-tive lead will often be indicated by a band of arrows pointing to the negative lead .

Installing capacitors with the polarity backwards will make the circuit malfunction and quickly destroy the capacitor—even causing it to explode .

Band 1 Band 2 Band 3 Band 4 1st Digit 2nd Digit Multiplier Tolerance

6 8 x1,000 +/- 5%

68K +/- 5%K = 1,000

Blue

Read this band first (closest to an end)

Gray Orange Gold

BLACK 0 0 1 None +/- 20%

BROWN 1 1 10

RED 2 2 100

ORANGE 3 3 1,000

YELLOW 4 4 10,000

GREEN 5 5 100,000

BLUE 6 6 1,000,000

VIOLET 7 7

GRAY 8 8 0.01 +/- 10% SILVER

WHITE 9 9 0.1 +/- 5% GOLD

NegativePositive

+ 25μF

16μf

How to read resistor values Capacitor values


STEP 2

Solder the speaker plugUse a small screwdriver to remove the back panel of the speaker plug .

On the black and white speaker leads, push the insulation back 3/8" . Solder the white positive lead to the tip lug (center of the plug) .

Trim the black lead and solder it to the sleeve lug . The solder joints need to be neat so they won’t short against the metal case . See "Tips for great soldering" on page 11 .

Reassemble the plug and do a continuity test with your multimeter to make sure there’s no connection between the plug’s tip and its metal case (see page 53) .

Remove the cabinet’s two back panels to prepare for installing the speaker .

STEP 1

Mount the power cord clampDrill a 5/64" pilot hole to mount the power cord clamp . Locate the clamp inside the left wall of the cabinet, 1” f rom the back panel ledge, 8” from the bottom .

Don’t drill through the cabinet! Use a piece of masking tape on your drill bit to mark the depth, or use a StewMac Depth-stop Drill Bit (item #1712) .

Use the black wood screw to mount the power cord clamp . You’ll secure the power cord with this clamp later, after the testing .

Start by prepping the cabinet

STEP 3

Solder the speaker leadsTwist the speaker leads together to keep them neat .

Push the insulation back 3/8" and insert the white lead into the speaker’s positive terminal and the black lead through the negative terminal .

Before soldering these leads, place a business card or other protection under the terminals to prevent solder dripping onto the speaker cone . Solder the two leads to the speaker terminals .

Check off eachcompleted step

Back

Here


STEP 5

Install faceplate + backplateSecure the faceplate by putting the normal channel volume and bass control pots in their holes and sliding the faceplate over them . Install washers and nuts on the pots to hold the plate in place .

Use the 1MA pot for volume and a 250KA pot for bass . Install them with their lugs facing up for soldering . See the wiring diagram on Page 12 .

Install the backplate the same way, using the two-lug extension speaker jack and the three-lug ground switch .

This switch is just for looks, because ground switches are not needed in modern amps with three-wire grounding power cords . But having it there keeps the vintage 1960s look .

Mount the ground switch so it toggles left/right rather than up/down .

STEP 6

Glue the tube placement chartCut out the tube replacement chart on page 63 . Put a thin coat of glue or contact cement on the back and glue it to the inside wall of the cabinet .

STEP 7

Reverb wiring kitThe shielded wire is in two 3-foot lengths . At the ends of each piece, pull 3/4" of the wire mesh shielding away to one side and strip away 3/8" of the internal cloth shielding . Insert the exposed wire into an RCA plug so that it reaches the tip of the center post .

Solder this lead in place at the tip of the plug . Don’t leave solder on the outside of the plug tip, which would keep it from fitting into the jack . See “Tips for great soldering” on page 11 .

After the plug tip cools and the inside solder joint is set, solder the braided wire shielding onto the outside of the plug . Solder the four RCA plugs this way, on each end of the two cables .

These two cables will connect the reverb tank .

Test for continuity between the tips of the plugs on each cable, then test for continuity between the shields of the plugs in the same way .

Also test to make sure you don’t have continuity between the tip and the shield of each plug, which would indicate a short in the cable . If your multimeter finds unwanted continu-ity, the likely culprit is the inside (tip) wire shorting to the outer shield . If that happens, de-solder the tip con-nection and redo that solder joint .

STEP 4

Install the speakerRemove the nuts from the four speaker-mounting screws . Carefully slide the speaker onto the mounting screws until it’s flush with the front panel .

Install the four speaker-mounting nuts so they’re lightly touching the speaker frame .

Do not tighten the nuts in a circular pattern around the speaker, because this can warp the speaker frame .

Instead tighten one nut with a quarter turn so it’s just snug, then do the same to the opposite side . Then snug the third nut and fourth . Repeat this criss-cross pattern of quarter-turns until all four nuts have had one full turn . This will give proper tension to compress the speaker gasket . Overtightening can warp the frame, damage the cone, and cause unwanted distortion .

Criss-cross tightening prevents warping.

’66 D-Reverb 22WO R I G I N A L A B 7 6 3 C I R C U I T

StewMac®

I C O N K I T S

Use only 1-amp slow-blow fuse, size 5mm x 20mm.

DANGER: Unplug the amp before changing tubes.Tube locations from left to right:

12AX7(ECC83)

12AX7(ECC83)

V5 V4

6V6 12AT7(ECC81)

V7 V6

12AX7(ECC83)

12AX7(ECC83)

V2 V1

12AT7(ECC81)

V3

5AR4(GZ34)

6V6

V9 V8

#10737


Prepping the eyelet boards

This circuit is built on three eyelet boards: the large main eyelet board, the middle-sized filter cap board, and the small bias board . Gather those three boards now .

STEP 8

Number the eyelets and holesIn these instructions, we’ll refer to the eyelets and holes on the main eyelet board by number . On the bias board and filter cap board, we’ll use letters . Orient the boards as shown below and use a pencil to add the numbers and letters .

L

S

K

RQ

J

P

I

O

H

M

G

N

38

28

1 2 34

56 7 8

51 52

10

34

54

68

58

43

4950

3231

61

4435 36

60

6362

45

36

11

55

41

1214 15

56

42

16

1921

2326

29

46

64

39

4748

30

6566

67

53

9

69 70

71 72

59

5773

7440

13

20 22

27

1817

2524

8385 86 87

90 91 92

94979695

93

98

37

88 89

99

7677

7881

82

79 80

33

84

75A

BC

D

F

E

Main

Bias Filter cap

STEP 10

Drill the filter cap boardsDrill 1/4" holes in the two upper cor-ners of the taped-together filter cap board and insulator (holes G and M) . Drill a third 1/4" hole centered be-tween eyelets P and R (hole Q) .

Separate the boards and set the insu-lator board aside .

The red dots on these boards indicate holes you’ll drill in the next steps . The main board and bias board each get two small mounting holes that don’t need to be numbered .

The filter cap board will get three holes drilled for wires to pass through (holes G, M, and Q) . Even though those holes aren’t there yet, mark the letters as shown while labeling the rest of the holes .

Insulator

Main eyelet board

Filter cap board

Bias boardInsulator

Insulator

Write these numbers + letterson the boards:

M

Q

G

STEP 9

Match the boards + insulatorsFor each of these three boards there is a matching blank insulator board of the same size . These insulators will be mounted behind the eyelet boards to keep the electrical connections from touching the metal chassis .

Align the three insulator boards behind their eyelet boards . Tape the pairs of boards together, to keep them aligned for the next step .


STEP 11

Drill the bias boardsThe small bias board mounts near the front left corner inside the chassis as indicated by the dotted line in the photo above . Center the taped bias board and insulator over the two mounting holes . Holding the boards in place inside the chassis, use a sharp pencil from the outside to mark the location of the two mounting holes onto the boards . Drill two 3/16" mounting holes, then separate the boards and set the insulator aside .

STEP 12

Drill the main boardsThe main eyelet board needs to be centered between the grommet holes circled in red above .

The right end of the board is 1/2" from the side of the chassis . Position the taped main board and insulator as indicated by the dotted lines .

Mark the mounting holes as you did with the bias boards . Drill two 3/16" mounting holes through these boards and set the insulator aside .

n Don’t think of solder as glue . Good mechanical connections make good electrical connections . Solder’s job is to finalize an already good joint, not to hold the parts on the board . So wrap the leads tightly for good electrical contact before soldering .

n Melt a small amount of solder onto the tip of the iron (“tinning" the iron) . Hold the tip against the joint for a few seconds, until the connection reaches soldering temperature .

Also tin component leads like multi-strand wires to help the solder flow .

Tips for great soldering!n Keep your soldering tip clean by wiping it often on a damp sponge . Keep it tinned by occasionally melting a little solder onto it .

n Feed solder to the connection not to the iron . Keep the iron on the con-nection for a second longer to allow time for all of the flux to cook out of the joint .

n Don’t ever blow on the hot solder or touch anything until the joint is completely cool . A good solder joint is shiny—a sign that it was left to cool undisturbed .

n Trim away the excess wires after the joint has cooled .

n Plan ahead so each joint is only soldered once . Resoldered joints are messy and more likely to fail .

n Position the parts so their specs face out so you can read them later . Many builders also align resistor bands to read in the same direction .

n How much insulation to strip? With plastic insulation, strip 3/8" from the wire ends . Push-back wire works best when you strip away about 1/4" of the cloth wrap .

stew

mac

.com

12

©

2019

Ste

wM

ac

NO

RMA

LV

OLU

ME

TREB

LEB

ASS

VO

LUM

ETR

EBLE

BA

SSRE

VER

BPI

LOT

SPEE

DIN

TEN

SITY

VIB

RAT

O

21

21

REV

ERB

INPU

TRE

VER

B

OU

TPU

TRE

VER

B

PED

AL

VIB

RAT

OPE

DA

LEX

T. S

PKR

SPEA

KER

STA

ND

BYPO

WER

FUSE

GRO

UN

D

V1

12A

X7

V2

12A

X7

V3

12A

T7V

412

AX

7V

512

AX

7V

612

AT7

V7

6V6

V8

6V6

V9

5AR4

OUTPUT TRANSFORMER(Mounted outside)

POW

ER T

RA

NSF

ORM

ER

FILTER CHOKE(Mounted outside)

REVERB DRIVER

(Mounted outside)

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

4 3

21

87

65

4 3

21

87

65

4 3

21

87

65

250KA

1MA

Sold

er

Wra

p

Snip

3 lu

gs e

lect

rical

lyjo

ined

sha

re a

com

mon

gro

und

Snip

stew

mac

.com

13

©

2019

Ste

wM

ac

Inst

alli

ng

th

e ch

assi

s-m

ou

nte

d c

om

po

nen

ts

S

TE

P 1

3

Mo

un

t th

e p

ow

er t

ran

sfo

rmer

+

two

th

ree-

lug

gro

un

din

g s

trip

sTh

e p

ower

tra

nsfo

rmer

has

ten

lea

ds

colo

r-co

ded

in f

our

pairs

, plu

s a

sing

le

red/

yello

w st

riped

lead

and

a si

ngle

red/

blue

str

iped

lead

. Tw

ist

the

sam

e-co

lor

pairs

tog

ethe

r . Fe

ed t

he le

ads

into

the

ch

assi

s th

roug

h th

e sq

uare

hol

e .

Unc

over

the

mou

ntin

g bo

lts a

nd in

stal

l th

e tr

ansf

orm

er o

n th

e ou

tsid

e of

the

ch

assi

s, w

ith f

our

8-32

lock

nuts

insi

de .

Mou

nt t

he t

wo

grou

ndin

g st

rips

at t

he

corn

ers

as s

how

n .

S

TE

P 14

Inst

all s

ix r

ub

ber

gro

mm

ets

Squ

eeze

th

ese

into

th

e si

x h

ole

s as

sh

own .

The

se p

rovi

de st

rain

relie

f for

the

wire

s th

at w

ill p

ass

thro

ugh

the

met

al

chas

sis .

S

TE

P 1

5

Mo

un

t th

e o

utp

ut

tran

sfo

rmer

The

outp

ut t

rans

form

er h

as r

ed, b

lue,

br

own,

bla

ck, a

nd g

reen

lead

s . T

wis

t the

br

own

and

blue

lead

s to

geth

er a

nd th

e gr

een

and

blac

k le

ads

toge

ther

.

Thre

ad th

e gr

een

and

blac

k lea

ds th

roug

h on

e ru

bber

gro

mm

et a

s sh

own .

Thr

ead

the

red,

bro

wn

and

blue

lead

s th

roug

h th

e gr

omm

et to

the

left

as

show

n .

Use

tw

o 8

-32

mac

hin

e sc

rew

s an

d lo

cknu

ts t

o m

ount

the

tra

nsfo

rmer

to

the

outs

ide

of th

e ch

assi

s .

S

TE

P 1

6

Mo

un

t th

e re

verb

dri

ver

The

reve

rb d

river

has

red,

blu

e, g

reen

, and

bl

ack

lead

s . T

hrea

d al

l fou

r lea

ds th

roug

h th

e on

e gr

omm

et a

nd tw

ist t

he g

reen

and

bl

ack

lead

s as

sho

wn .

Use

tw

o 8

-32

mac

hin

e sc

rew

s an

d lo

cknu

ts t

o m

ount

the

rev

erb

driv

er t

o th

e ou

tsid

e of

the

chas

sis .

S

TE

P 1

7

Mo

un

t th

e fi

lter

ch

oke

The

filt

er c

hoke

has

tw

o b

lack

lea

ds .

Thre

ad t

hem

thr

ough

the

gro

mm

eted

ho

le w

ith th

e re

d, b

lue,

and

bro

wn

outp

ut

tran

sfor

mer

lead

s .

Use

tw

o 8

-32

mac

hin

e sc

rew

s an

d lo

cknu

ts to

mou

nt th

e fil

ter c

hoke

out

side

of

the

chas

sis .

S

TE

P 1

8

Inst

all t

he

spea

ker

ou

tpu

t ja

ckA

dd t

he t

hree

-lug

spea

ker

outp

ut ja

ck

next

to

the

two-

lug

exte

nsio

n sp

eake

r ja

ck, w

hich

you

’ve

alre

ady

inst

alle

d .

Thes

e ja

cks

are

elec

tric

ally

gro

unde

d th

roug

h co

ntac

t with

the

met

al c

hass

is,

so ti

ghte

n th

em w

ell f

or a

goo

d gr

ound

.

S

TE

P 19

Inst

all t

he

thre

e la

rge

tub

e so

cket

s w

ith

ten

sio

n c

lip

sO

rient

the

se e

ight

-pin

tub

e so

cket

s so

th

at p

in 1

is c

lose

st t

o th

e re

ar p

anel

of

the

chas

sis .

Use

two

4-40

x 3

/8" m

achi

ne s

crew

s and

lo

cknu

ts to

mou

nt th

ese

sock

ets

on th

e ou

tsid

e of

the

chas

sis .

Incl

ude

a te

nsio

n cl

ip o

n th

e b

otto

m o

f ea

ch s

ocke

t to

pr

ovid

e su

ppor

t for

the

thre

e tu

bes w

hen

they

’re in

stal

led

late

r .

S

TE

P 2

0

Inst

all t

he

six

smal

l tu

be

sock

ets

Use

two

4-40

x 1

/4" m

achi

ne s

crew

s an

d lo

cknu

ts to

mou

nt th

e si

x re

mai

ning

tube

so

cket

s . P

ositi

on th

ese

sock

ets s

o pi

n 3

is

clos

est t

o th

e re

ar p

anel

of t

he c

hass

is .

S

TE

P 2

1

Inst

all t

he

bia

s p

ot

+ o

ne

resi

sto

rM

ount

the

10KL

bia

s pot

in th

e flo

or o

f the

ch

assi

s as s

how

n . W

rap

one

lead

of a

10K

re

sist

or t

hrou

gh t

he le

ft lu

g of

the

bia

s po

t an

d so

lder

it in

to p

lace

. Sol

der

the

othe

r lea

d of

this

resi

stor

to th

e ho

usin

g of

the

bia

s po

t . It

does

n’t

mat

ter

whi

ch

dire

ctio

n th

is re

sist

or is

inst

alle

d, b

ecau

se

resi

stor

s ar

en’t

pola

rized

.

S

TE

P 2

2

Inst

all t

he

fuse

so

cket

Mou

nt t

he f

use

sock

et s

o it

s si

de lu

g fa

ces

the

open

sid

e of

the

cha

ssis

. Thi

s or

ient

atio

n m

akes

it e

asie

r to

sold

er la

ter .

S

TE

P 2

3

Inst

all t

he

po

wer

sw

itch

+

the

stan

db

y sw

itch

Mou

nt th

e po

wer

switc

h an

d th

e st

andb

y sw

itch

with

thei

r lug

s fa

cing

up

for e

asy

sold

erin

g la

ter .

S

TE

P 2

4

Inst

all t

he

fou

r R

CA

jack

sM

ount

th

e RC

A j

acks

to

the

chas

sis

with

the

larg

e w

ashe

rs o

n th

e ou

tsid

e .

Onc

e in

stal

led

, b

end

the

gro

und

ing

tabs

slig

htly

aw

ay fr

om th

e in

side

of t

he

chas

sis .

stew

mac

.com

14

©

2019

Ste

wM

ac

NO

RMA

LV

OLU

ME

TREB

LEB

ASS

VO

LUM

ETR

EBLE

BA

SSRE

VER

BPI

LOT

SPEE

DIN

TEN

SITY

VIB

RAT

O

21

21

REV

ERB

INPU

TRE

VER

B

OU

TPU

TRE

VER

B

PED

AL

VIB

RAT

OPE

DA

LEX

T. S

PKR

SPEA

KER

STA

ND

BYPO

WER

FUSE

GRO

UN

D

V1

12A

X7

V2

12A

X7

V3

12A

T7V

412

AX

7V

512

AX

7V

612

AT7

V7

6V6

V8

6V6

V9

5AR4

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

4 3

21

87

65

4 3

21

87

65

4 3

2

65

4 3

21

87

65

1MA

1MA

250KA

250KA

100KL

3MRA

50KRA

250KA

250KA

47

stew

mac

.com

15

©

2019

Ste

wM

ac

S

TE

P 2

5

Inst

all t

he

pil

ot

lam

p s

ock

etM

ou

nt

the

sock

et b

y sc

rew

ing

th

e le

ns f

rom

the

out

side

into

the

soc

ket

asse

mbl

y . P

ositi

on th

e so

cket

so th

e ar

m

supp

ortin

g th

e la

mp

face

s th

e si

de w

all

of t

he c

hass

is a

nd t

he t

abs

face

up

for

sold

erin

g .

Som

e am

p bu

ilder

s add

a d

rop

of g

lue

to

the

mou

ntin

g th

read

s to

keep

vib

ratio

ns

from

hig

h-vo

lum

e pl

ayin

g fro

m lo

osen

ing

the

sock

et .

S

TE

P 2

6

Inst

all t

he

rem

ain

ing

co

ntr

ol p

ots

Mou

nt th

e co

ntro

l pot

s so

thei

r thr

ee lu

gs

are

faci

ng t

he c

hass

is o

peni

ng . W

hen

we

refe

r to

thes

e lu

gs a

s le

ft o

r rig

ht, i

t’s

assu

min

g yo

u’re

look

ing

at th

e po

t fro

m

the

sam

e p

oint

of

view

as

the

wir

ing

diag

ram

. Mou

nt th

em a

s fo

llow

s:

Vi

brat

o Ch

anne

l Int

ensi

ty: 5

0KRA

pot

Vi

brat

o Ch

anne

l Spe

ed: 3

MRA

pot

Vi

brat

o Ch

anne

l Rev

erb:

100

KL p

ot

Vibr

ato

Chan

nel B

ass:

250K

A p

ot

Vibr

ato

Chan

nel T

rebl

e: 2

50KA

pot

Vi

brat

o Ch

anne

l Vol

ume:

1M

A p

ot

Nor

mal

Cha

nnel

Tre

ble:

250

KA p

ot

S

TE

P 2

7

Inst

all t

wo

res

isto

rsRu

n o

ne

lead

of

a 10

0K r

esis

tor

up

thro

ugh

the

bott

om o

f the

left

lug

of th

e sp

eed

pot a

nd w

rap

it do

wn

thro

ugh

the

mid

dle

lug

of t

he s

ame

pot .

Sold

er t

he

resi

stor

lead

to b

oth

lugs

.

Sold

er t

he o

ther

lead

of

this

res

isto

r to

th

e ba

ck o

f the

spe

ed p

ot .

Wra

p on

e le

ad o

f a 6

.8K

resi

stor

thro

ugh

the

left

lug

of t

he v

ibra

to c

hann

el b

ass

pot a

nd s

olde

r the

lead

to th

is lu

g .

Sold

er t

he 6

.8K

resi

stor

’s ot

her

lead

to

the

back

of t

he v

ibra

to c

hann

el b

ass p

ot .

S

TE

P 2

8

Inst

all o

ne

cap

acit

or

+ o

ne

resi

sto

rRu

n o

ne

lead

of

the

47p

F ca

pac

itor

th

roug

h th

e m

iddl

e lu

g of

the

vib

rato

ch

anne

l vol

ume

pot .

Run

the

othe

r lea

d of

thi

s ca

p th

roug

h th

e rig

ht lu

g of

the

vi

brat

o ch

anne

l vol

ume

pot .

Wra

p th

ese

lead

s aro

und

thes

e lu

gs b

ut d

o no

t sol

der

them

yet

.

Wra

p on

e le

ad o

f a 6

.8K

resi

stor

thro

ugh

the

left

lug

of t

he n

orm

al c

hann

el b

ass

pot a

nd s

olde

r the

lead

to th

is lu

g .

Sold

er t

he 6

.8K

resi

stor

’s ot

her

lead

to

the

back

of t

he n

orm

al c

hann

el b

ass p

ot .

S

TE

P 2

9

Inst

all t

wo

jum

per

sCu

t tw

o 2"

yel

low

jum

pers

.

Wra

p on

e en

d of

the

first

jum

per t

hrou

gh

the

mid

dle

lug

of t

he v

ibra

to c

hann

el

bass

pot

and

wra

p th

e ot

her e

nd o

f thi

s ju

mpe

r thr

ough

the

left

lug

of th

e vi

brat

o ch

anne

l tre

ble

pot .

Sold

er th

is le

ad in

to

the

left

lug

of th

e tr

eble

pot

but

not

the

mid

dle

lug

of th

e ba

ss p

ot .

Wra

p o

ne

end

of

the

oth

er j

um

per

th

roug

h th

e m

iddl

e lu

g of

the

vib

rato

ch

anne

l tre

ble

pot a

nd th

e ot

her e

nd o

f th

e sa

me

jum

per t

hrou

gh th

e rig

ht lu

g of

th

e vi

brat

o ch

anne

l vol

ume

pot .

Sold

er

this

lead

into

bot

h lu

gs .

S

TE

P 3

0

Inst

all t

wo

mo

re ju

mp

ers

Cut t

wo

mor

e 2"

yel

low

jum

pers

.

Wra

p on

e en

d of

the

first

jum

per t

hrou

gh

the

mid

dle

lug

of t

he n

orm

al c

hann

el

bass

pot

and

wra

p th

e ot

her e

nd o

f thi

s ju

mpe

r thr

ough

the

left

lug

of th

e no

rmal

ch

anne

l tre

ble

pot .

Sold

er th

is le

ad in

to

the

left

lug

of th

e tr

eble

pot

but

not

the

mid

dle

lug

of th

e ba

ss p

ot .

Wra

p o

ne

end

of

the

oth

er j

um

per

th

roug

h th

e m

iddl

e lu

g of

the

nor

mal

ch

anne

l tre

ble

pot a

nd th

e ot

her e

nd o

f th

e sa

me

jum

per t

hrou

gh th

e rig

ht lu

g of

th

e no

rmal

cha

nnel

vol

ume

pot .

Sold

er

this

lead

into

bot

h lu

gs .

S

TE

P 3

1

Inst

all v

ibra

to c

han

nel

jack

s +

1M

res

isto

rA

dd v

ibra

to c

hann

el in

stru

men

t ja

cks

1 an

d 2 .

Pos

ition

them

so th

e ce

nter

lug

of

jack

2 is

clo

se to

the

left

lug

of ja

ck 1

as

pict

ured

.

Wra

p on

e le

ad o

f a 1

M r

esis

tor

thro

ugh

the

right

lug

of ja

ck 1

and

wra

p it

onto

th

e ce

nter

lug

of th

e sa

me

jack

. Mak

e su

re

the

lead

or t

he b

ody

of th

e re

sist

or w

on’t

be in

the

way

whe

n an

inst

rum

ent c

able

is

plu

gged

in .

Run

this

resi

stor

’s ot

her l

ead

thro

ugh

the

left

lug

of ja

ck 1

and

ont

o th

e ce

nter

lug

of

jack

2 . D

on’t

sold

er th

ese

conn

ectio

ns ye

t .

For ne

at loo

king w

iring,

use wi

re str

ippers

to

trim 1/

4" of t

he ins

ulation

fro

m the

ends o

f the

push-b

ack wi

re.

stew

mac

.com

16

©

2019

Ste

wM

ac

NO

RMA

LV

OLU

ME

TREB

LEB

ASS

VO

LUM

ETR

EBLE

BA

SSRE

VER

BPI

LOT

SPEE

DIN

TEN

SITY

VIB

RAT

O

21

21

REV

ERB

INPU

TRE

VER

B

OU

TPU

TRE

VER

B

PED

AL

VIB

RAT

OPE

DA

LEX

T. S

PKR

SPEA

KER

STA

ND

BYPO

WER

FUSE

GRO

UN

D

V1

12A

X7

V2

12A

X7

V3

12A

T7V

412

AX

7V

512

AX

7V

612

AT7

V7

6V6

V8

6V6

V9

5AR4

POW

ER T

RA

NSF

ORM

ER

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

4 3

21

87

65

4 3

21

87

65

4 3

2

65

4 3

21

87

65

stew

mac

.com

17

©

2019

Ste

wM

ac

S

TE

P 3

2

Inst

all t

wo

68

K r

esis

tors

on

th

e vi

bra

to c

han

nel

jack

sTw

ist

the

lead

s of

tw

o 68

K re

sist

ors

toge

ther

, cre

atin

g on

e co

nnec

tion .

Wra

p th

e ot

her l

ead

from

one

resi

stor

ont

o th

e rig

ht lu

g of

vib

rato

jack

2 a

s sh

own .

Wra

p th

e re

mai

ning

resi

stor

lead

ont

o th

e le

ft lu

g of

vib

rato

jack

1, a

ddin

g it

to th

e co

nnec

tion

mad

e in

the

prev

ious

ste

p .

Sold

er a

ll th

ese

conn

ectio

ns, a

nd a

lso

sold

er th

e tw

iste

d 68

K re

sist

or le

ads .

S

TE

P 3

3

Inst

all n

orm

al c

han

nel

jack

s +

1M

res

isto

rA

dd n

orm

al c

hann

el in

stru

men

t ja

cks

1 an

d 2 .

Pos

ition

them

so th

e ce

nter

lug

of

jack

2 is

clo

se to

the

left

lug

of ja

ck 1

as

pict

ured

.

Wra

p on

e le

ad o

f a 1

M r

esis

tor

thro

ugh

the

right

lug

of ja

ck 1

and

wra

p it

onto

th

e ce

nter

lug

of th

e sa

me

jack

. Mak

e su

re

the

lead

or t

he b

ody

of th

e re

sist

or w

on’t

be in

the

way

whe

n an

inst

rum

ent c

able

is

plu

gged

in .

Run

this

resi

stor

’s ot

her l

ead

thro

ugh

the

left

lug

of ja

ck 1

and

ont

o th

e ce

nter

lug

of

jack

2 . D

on’t

sold

er th

ese

conn

ectio

ns ye

t .

S

TE

P 3

4

Inst

all t

wo

68

K r

esis

tors

on

th

e n

orm

al c

han

nel

jack

sTw

ist

the

lead

s of

tw

o 68

K re

sist

ors

toge

ther

, cre

atin

g on

e co

nnec

tion .

Wra

p th

e ot

her l

ead

from

one

resi

stor

ont

o th

e rig

ht lu

g of

jack

2 a

s sh

own .

Wra

p th

e re

mai

ning

res

isto

r le

ad o

nto

the

left

lug

of ja

ck 1

, add

ing

it t

o th

e co

nnec

tion

mad

e in

the

prev

ious

ste

p .

Sold

er a

ll th

ese

conn

ectio

ns, a

nd a

lso

sold

er th

e tw

iste

d 68

K re

sist

or le

ads .

S

TE

P 3

5

Po

wer

tra

nsf

orm

er b

lack

lead

sRu

n ei

ther

of

the

blac

k w

ires

from

the

po

wer

tran

sfor

mer

to th

e si

de lu

g of

the

fuse

sock

et . T

rim it

to fi

t and

sold

er it

. Trim

an

d so

lder

the

othe

r bla

ck w

ire to

the

left

lu

g on

the

pow

er s

witc

h .

S

TE

P 3

6

Po

wer

tra

nsf

orm

er g

reen

lead

sRu

n th

e tw

o gr

een

wire

s fro

m th

e po

wer

tr

ansf

orm

er to

the

lugs

on

the

pilo

t lam

p so

cket

(eith

er w

ire c

an g

o to

eith

er lu

g) .

Trim

the

se w

ires

to

leng

th a

nd w

rap

them

ont

o th

e lu

gs . D

on’t

sold

er t

hese

co

nnec

tions

yet

.

S

TE

P 3

7

Po

wer

tra

nsf

orm

er r

ed/y

ello

w le

adTr

im th

e po

wer

tran

sfor

mer

’s re

d/ye

llow

le

ad to

an

appr

opria

te le

ngth

and

sold

er

it to

the

grou

ndin

g st

rip a

s sh

own .

S

TE

P 3

8

Po

wer

tra

nsf

orm

er r

ed le

ads

Trim

the

pow

er t

rans

form

er’s

red

lead

s to

an

appr

opria

te le

ngth

and

wra

p on

e le

ad o

nto

pin

4 of

soc

ket V

9 . T

he p

ins o

n th

e 8-

pin

sock

ets

have

upp

er a

nd lo

wer

ey

elet

s fo

r mul

tiple

con

nect

ions

.

Wra

p th

e ot

her

red

lead

ont

o pi

n 6

of

the

sam

e so

cket

. Don

’t so

lder

thes

e re

d le

ads

yet .

S

TE

P 3

9

Po

wer

tra

nsf

orm

er y

ello

w le

ads

Trim

the

pow

er tr

ansf

orm

er’s

yello

w le

ads

to a

n ap

prop

riate

leng

th . W

rap

one

of

thes

e le

ads

onto

pin

2 o

f soc

ket V

9 .

Wra

p th

e ot

her

yello

w le

ad o

nto

pin

8 of

the

sam

e so

cket

. Don

’t so

lder

the

se

yello

w le

ads

yet .

stew

mac

.com

18

©

2019

Ste

wM

ac

NO

RMA

LV

OLU

ME

TREB

LEB

ASS

VO

LUM

ETR

EBLE

BA

SSRE

VER

BPI

LOT

SPEE

DIN

TEN

SITY

VIB

RAT

O

21

21

REV

ERB

INPU

TRE

VER

B

OU

TPU

TRE

VER

B

PED

AL

VIB

RAT

OPE

DA

LEX

T. S

PKR

SPEA

KER

STA

ND

BYPO

WER

FUSE

GRO

UN

D

V1

12A

X7

V2

12A

X7

V3

12A

T7V

412

AX

7V

512

AX

7V

612

AT7

V7

6V6

V8

6V6

V9

5AR4

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

4 3

21

87

65

4 3

21

87

65

6

4321

98 7 5

4 3

21

87

65

V3

12A

T7

6

4321

98 7 5

stew

mac

.com

19

©

2019

Ste

wM

ac

S

TE

P 4

0

Ou

tpu

t tr

ansf

orm

er

blu

e +

bro

wn

lead

sTr

im t

he

blu

e w

ire

from

th

e ou

tput

tr

ansf

orm

er t

o an

app

ropr

iate

len

gth

and

wra

p it

onto

pin

3 o

f soc

ket V

7 . D

on’t

sold

er th

is c

onne

ctio

n ye

t .

Trim

the

bro

wn

wire

fro

m t

he o

utpu

t tr

ansf

orm

er t

o an

app

ropr

iate

len

gth

and

wra

p it

onto

pin

3 o

f soc

ket V

8 . D

on’t

sold

er th

is c

onne

ctio

n ye

t .

Leav

e th

e re

d ou

tput

tra

nsfo

rmer

lead

fr

ee fo

r now

; you

'll c

onne

ct it

late

r, w

hen

the

eyel

et b

oard

is in

stal

led .

S

TE

P 4

1

Ad

d t

wo

jum

per

sA

dd a

1-1

/2" y

ello

w ju

mpe

r bet

wee

n th

e rig

ht lu

g of

the

spea

ker j

ack

and

the

right

lu

g of

the

ext

ensi

on ja

ck . W

rap

thes

e jo

ints

, but

do

not s

olde

r the

m y

et .

Cut a

3/4

" yel

low

jum

per a

nd re

mov

e th

e in

sula

tion .

Add

thi

s sh

ort

wire

bet

wee

n th

e sp

eake

r jac

k’s l

eft l

ug a

nd c

ente

r lug

. So

lder

the

both

end

s .

S

TE

P 4

2

Ou

tpu

t tr

ansf

orm

er

gre

en +

bla

ck le

ads

Trim

thes

e tw

o w

ires t

o re

ach

the

spea

ker

jack

and

ext

ensi

on s

peak

er ja

ck .

Sold

er th

e gr

een

lead

to th

e rig

ht lu

g of

th

e sp

eake

r ja

ck a

long

with

the

jum

per

from

the

prev

ious

ste

p .

Sold

er th

e bl

ack

lead

to th

e le

ft lu

g of

the

exte

nsio

n sp

eake

r jac

k .

S

TE

P 4

3

Co

nn

ect

the

reve

rb d

rive

r le

ads

Trim

the

gree

n le

ad to

reac

h th

e m

iddl

e lu

g of

the

rev

erb

inpu

t ja

ck, t

in it

and

so

lder

it to

the

lug .

Trim

the

blac

k le

ad to

reac

h th

e gr

ound

tab

on th

e re

verb

inpu

t ja

ck . T

in it

and

sol

der

it to

thi

s ta

b .

Trim

the

blue

lead

to re

ach

pin

6 of

sock

et

V3 . T

in it

and

wra

p it

onto

the

pin

, but

do

n’t s

olde

r it y

et .

Leav

e th

e re

d le

ad fr

ee fo

r now

; you

will

in

stal

l it t

o th

e ey

elet

boa

rd la

ter o

n .

S

TE

P 4

4

Ad

d t

hre

e ye

llo

w ju

mp

ers

Cut t

wo

1" y

ello

w ju

mpe

rs . W

rap

one

of

them

bet

wee

n pi

n 2

and

pin

7 of

soc

ket

V3 . S

olde

r the

con

nect

ion

to p

in 2

.

Wra

p th

e se

cond

shor

t jum

per b

etw

een

pin

3 an

d pi

n 8

of s

ocke

t V3 .

Sol

der t

he

conn

ectio

n to

pin

3 .

Cut a

2-1

/2" y

ello

w ju

mpe

r and

conn

ect i

t be

twee

n pi

ns 1

and

6 o

n so

cket

V3 .

Rou

te

this

jum

per

in a

sem

icirc

le a

roun

d th

e ba

ck o

f the

soc

ket .

Sold

er th

is ju

mpe

r at

pin

1 an

d al

so a

t pin

6 w

here

it jo

ins

the

blue

wire

from

the

reve

rb d

river

.

S

TE

P 4

5

Ad

d t

hre

e m

ore

yel

low

jum

per

sCu

t one

2-1

/2" y

ello

w ju

mpe

r . W

rap

one

end

of th

is ju

mpe

r in

pin

8 of

soc

ket V

1 .

Wra

p th

e ot

her e

nd o

f thi

s jum

per i

n pi

n 8

of s

ocke

t V2 .

Sol

der t

he c

onne

ctio

n at

pi

n 8

of V

1 .

Cut t

wo

1" y

ello

w ju

mpe

rs . W

rap

one

of

them

bet

wee

n pi

n 3

and

pin

8 of

soc

ket

V4 . S

olde

r the

con

nect

ion

at p

in 3

.

Wra

p th

e se

cond

sho

rt ju

mpe

r bet

wee

n pi

n 3

and

pin

8 of

soc

ket V

6 . S

olde

r the

co

nnec

tion

at p

in 3

.

Gro

und

tab

stew

mac

.com

2

0

©20

19 S

tew

Mac

NO

RMA

LV

OLU

ME

TREB

LEB

ASS

VO

LUM

ETR

EBLE

BA

SSRE

VER

BPI

LOT

SPEE

DIN

TEN

SITY

VIB

RAT

O

21

21

REV

ERB

INPU

TRE

VER

B

OU

TPU

TRE

VER

B

PED

AL

VIB

RAT

OPE

DA

LEX

T. S

PKR

SPEA

KER

STA

ND

BYPO

WER

FUSE

GRO

UN

D

V1

12A

X7

V2

12A

X7

V3

12A

T7V

412

AX

7V

512

AX

7V

612

AT7

V7

6V6

V8

6V6

V9

5AR4

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

4 3

21

87

65

6

4321

98 7 5

4 3

21

87

65

4 3

21

87

65

stew

mac

.com

2

1

©20

19 S

tew

Mac

S

TE

P 4

6

Ad

d t

wo

jum

per

s +

on

e re

sist

or

Cut o

ne 1

-1/4

” ye

llow

jum

per .

Wra

p on

e en

d th

roug

h th

e m

iddl

e lu

g of

the

reve

rb

outp

ut R

CA ja

ck a

nd w

rap

the

othe

r end

th

roug

h th

e m

iddl

e lu

g of

the

rev

erb

peda

l RCA

jack

. Sol

der t

his j

umpe

r to

the

reve

rb o

utpu

t RCA

jack

.

Add

a 2

20K

resi

stor

bet

wee

n th

e m

iddl

e lu

g of

the

reve

rb p

edal

RCA

jack

and

the

grou

nd lu

g of

the

vibr

ato

peda

l RCA

jack

. So

lder

it in

to th

e gr

ound

lug

of th

e re

verb

ou

tput

RCA

jack

.

Cut

a 3-

1/2”

yel

low

jum

per .

Wra

p on

e en

d th

roug

h th

e m

iddl

e lu

g of

the

reve

rb

outp

ut R

CA ja

ck a

nd w

rap

the

othe

r end

th

roug

h pi

n 2

of s

ocke

t V4

. Sol

der

this

ju

mpe

r at b

oth

ends

.

S

TE

P 4

7

Ad

d fo

ur

resi

sto

rsA

dd o

ne 1

.5K

resi

stor

bet

wee

n pi

n 1

and

pin

5 of

soc

ket

V7 . S

olde

r bo

th le

ads

in

to p

lace

.

Add

one

1 .5

K re

sist

or b

etw

een

pin

1 an

d pi

n 5

of s

ocke

t V8

. Sol

der

both

lead

s in

to

pla

ce .

Add

one

470

Ω 1

W re

sist

or b

etw

een

pin

4 an

d pi

n 6

of so

cket

V7 .

Sta

nd th

is re

sist

or

up o

ff t

he s

ocke

t ab

out

half

an i

nch .

So

lder

the

lead

wra

pped

in p

in 4

.

Add

one

470

Ω 1

W re

sist

or b

etw

een

pin

4 an

d pi

n 6

of so

cket

V8 .

Sta

nd th

is re

sist

or

up o

ff t

he s

ocke

t ab

out

half

an i

nch .

So

lder

the

lead

wra

pped

in p

in 4

.

S

TE

P 4

8

Ad

d t

hre

e ju

mp

ers

Cut

one

3-1/

2" y

ello

w j

ump

er . S

olde

r on

e en

d to

pin

6 o

f soc

ket V

8 . W

rap

one

end

onto

pin

6 o

f soc

ket

V7, b

ut d

o no

t so

lder

it y

et .

Cut o

ne 3

-1/2

" gre

en ju

mpe

r . So

lder

one

en

d to

pin

8 o

f soc

ket V

7 . W

rap

the

othe

r en

d on

to p

in 8

of s

ocke

t V8,

but

do

not

sold

er it

yet

.

Cut o

ne 3

" gre

en ju

mpe

r . W

rap

one

end

in p

in 8

of s

ocke

t V8 .

Wra

p th

e ot

her e

nd

thro

ugh

one

of th

e lu

gs o

f the

thre

e-lu

g gr

ound

ing

stri

p cl

oses

t to

soc

ket

V8 .

Sold

er b

oth

ends

of t

his

jum

per .

Sto

p a

nd

insp

ect

you

r w

ork

This

is a

goo

d tim

e to

step

aw

ay fr

om th

e pr

ojec

t fo

r a

few

min

utes

. Tak

e a

brea

k be

fore

revi

ewin

g yo

ur w

ork

for e

rror

s .

Whe

n yo

u’re

read

y to

go

at it

aga

in, v

ery

care

fully

wal

k th

roug

h ev

ery

conn

ectio

n yo

u’ve

mad

e so

far

. Whe

n ev

eryt

hing

ch

ecks

out

, you

’re r

eady

to

mov

e on

to

the

eyel

et b

oard

.

STOP

Be sus

piciou

s The

re's a

mistak

e, and

you’re

gonna

find it!

stew

mac

.com

2

2

©20

19 S

tew

Mac

AB

CD

FE

+

25µ

F

How

to

inst

all p

arts

on

an

eye

let

bo

ard

in t

hre

e st

eps

Wra

p

Don

’t so

lder

the

com

pone

nts

as t

hey

go

onto

th

e ey

elet

b

oard

. Ins

tead

wra

p a

ll th

e pa

rts o

nto

the

boar

d, b

endi

ng

thei

r lea

ds ti

ghtly

so

the

part

s st

ay in

pla

ce w

ithou

t sol

der .

Insp

ect

Whe

n al

l the

par

ts a

re in

pla

ce,

stop

and

insp

ect .

Go

back

ove

r ev

ery

step

. Car

eful

insp

ectio

n is

the

bes

t w

ay t

o m

ake

sure

yo

ur a

mp

wor

ks th

e fir

st ti

me

you

turn

it o

n .

Sold

erSo

lder

eac

h co

nnec

tion

poin

t on

ly o

nce .

Reh

eatin

g to

add

an

othe

r pa

rt m

akes

a m

essy

, fa

ulty

sol

der

joi

nt .

Use

the

so

lder

ing

tips

on p

age

11 t

o ge

t pro

fess

iona

l res

ults

.

stew

mac

.com

2

3

©20

19 S

tew

Mac

Wra

pp

ing

par

ts o

nto

th

e b

ias

bo

ard

The

bias

boa

rd i

s th

e sm

alle

st o

f th

e th

ree

eyel

et b

oard

s . P

ositi

on it

as s

how

n ab

ove,

with

hol

e D

to

the

uppe

r rig

ht,

and

the

pair

of m

ount

ing

hole

s to

war

d th

e bo

ttom

.

S

TE

P 4

9

Ad

d o

ne

resi

sto

rA

dd a

470

Ω 1

W re

sist

or b

etw

een

eyel

ets

A a

nd B

.

Don

’t so

lder

the

se c

onne

ctio

ns . Y

ou’ll

so

lder

the

con

nect

ions

on

both

eye

let

boa

rds

late

r, af

ter

all

thei

r p

arts

are

w

rapp

ed in

pla

ce a

nd d

oubl

e-ch

ecke

d .

S

TE

P 5

0

Ad

d a

cap

acit

or

and

a d

iod

eAd

d a 2

5μF e

lect

roly

tic ca

paci

tor b

etw

een

eyel

ets E

and

F . N

ote

the

po

lari

ty o

f th

e ca

pac

ito

r. C

onne

ct t

he c

ap’s

nega

tive

lead

to e

yele

t F .

Add

the

rect

ifier

dio

de b

etw

een

eyel

ets B

an

d C .

Not

e th

e po

larit

y . T

he p

ositi

ve le

ad

of th

e di

ode

is in

dica

ted

by a

strip

e at

that

en

d . T

he e

nd w

ith n

o st

ripe

is n

egat

ive .

Co

nnec

t the

neg

ativ

e le

ad to

eye

let C

.

S

TE

P 5

1

Ad

d t

wo

jum

per

sCu

t a 1

-1/8

" ye

llow

jum

per .

Flip

the

bias

bo

ard

over

and

add

this

jum

per b

etw

een

eyel

ets C

and

F o

n th

e ba

ck o

f the

boa

rd .

Cut

a 4"

yel

low

jum

per .

Wra

p on

e en

d th

roug

h ey

elet

C a

nd ru

n th

e re

st d

own

thro

ugh

hole

D . P

ull i

t tig

ht to

kee

p it

in

plac

e .

S

TE

P 5

2

Ad

d o

ne

jum

per

Cut

one

7" g

reen

jum

per

and

wra

p on

e en

d th

roug

h ey

elet

E .

Set

the

bia

s b

oar

d a

sid

eSt

ore

the

bias

boa

rd s

omew

here

tha

t it

won

’t be

dis

turb

ed . Y

ou’re

rea

dy t

o tu

rn y

our

atte

ntio

n to

the

filt

er c

ap

eyel

et b

oard

.

stew

mac

.com

24

©

2019

Ste

wM

ac

G

NH

OI

PJ

RK

SLM

Q

16μF

16μF

16μF

16μF

16μF

stew

mac

.com

2

5

©20

19 S

tew

Mac

The

filte

r cap

boa

rd is

the

med

ium

-siz

ed

of th

e th

ree

eyel

et b

oard

s . P

ositi

on it

as

show

n ab

ove,

with

the

thro

ugh

hole

s in

th

e to

p tw

o co

rner

s .

S

TE

P 5

3

Ad

d fi

ve c

apac

ito

rsAd

d a 1

6μF

elec

trol

ytic

capa

cito

r bet

wee

n ey

elet

s H

and

N . N

ote

the

pola

rity

of th

e ca

paci

tor .

Conn

ect

the

cap’

s ne

gati

ve

lead

to e

yele

t N .

Add

ano

ther

16μ

F el

ectr

olyt

ic c

apac

itor

betw

een

eyel

ets I

and

O . N

ote

the

pola

rity

of

the

cap

acit

or .

Co

nn

ect

the

cap

’s

nega

tive

lead

to e

yele

t O .

Add

a t

hird

16μ

F el

ectr

olyt

ic c

apac

itor

betw

een

eyel

ets J

and

P . N

ote

the

pola

rity

of

the

cap

acit

or .

Co

nn

ect

the

cap

’s

nega

tive

lead

to e

yele

t P .

Add

a fo

urth

16μ

F el

ectr

olyt

ic c

apac

itor

bet

wee

n e

yele

ts K

an

d R

. N

ote

th

e po

larit

y of

the

cap

acito

r . Co

nnec

t th

e ca

p’s

nega

tive

lead

to e

yele

t R .

Add

a fi

fth

16μF

ele

ctro

lytic

cap

acito

r be

twee

n ey

elet

s L a

nd S

. Not

e th

e po

larit

y o

f th

e ca

pac

ito

r . C

on

nec

t th

e ca

p’s

ne

gativ

e le

ad to

eye

let S

.

S

TE

P 5

4

Ad

d fo

ur

jum

per

sCu

t fou

r 1-1

/2" g

reen

jum

pers

.

Wra

p th

e fir

st b

etw

een

eyel

ets

N a

nd O

.

Wra

p t

he s

econ

d b

etw

een

eyel

ets

O

and

P .

Wra

p th

e th

ird b

etw

een

eyel

ets

R an

d S .

Wra

p th

e fo

urth

bet

wee

n ey

elet

s K a

nd L

.

S

TE

P 5

5

Ad

d t

wo

res

isto

rsA

dd a

10K

2W

res

isto

r be

twee

n ey

elet

s H

and

I .

Add

ano

ther

10K

2W

res

isto

r be

twee

n ey

elet

s I a

nd J .

S

TE

P 5

6

Ad

d fo

ur

jum

per

sCu

t tw

o 6"

gre

en ju

mpe

rs .

Wra

p on

e en

d of

one

thr

ough

eye

let

S .

Pull

the

othe

r en

d th

roug

h ho

le M

and

pu

ll it

tight

to k

eep

it in

pla

ce .

Wra

p o

ne

end

of

the

oth

er j

um

per

th

roug

h ey

elet

N . P

ull

the

othe

r en

d th

roug

h ho

le G

and

pul

l it t

ight

to k

eep

it in

pla

ce .

Cut t

wo

6" y

ello

w ju

mpe

rs a

nd tw

ist t

hem

to

geth

er ti

ght .

Wra

p on

e en

d of

eac

h ju

mpe

r th

roug

h ey

elet

J .

Then

run

the

tw

iste

d l

eads

th

roug

h ho

le Q

and

pul

l the

m t

ight

to

keep

them

in p

lace

.

S

TE

P 5

7

Ad

d fo

ur

jum

per

sCu

t a

6" y

ello

w ju

mpe

r an

d w

rap

one

end

thro

ugh

eyel

et L

. Pul

l the

oth

er e

nd

thro

ugh

hole

M a

nd p

ull i

t tig

ht to

kee

p it

in p

lace

.

Cut

a 7"

yel

low

jum

per

and

wra

p on

e en

d th

roug

h ey

elet

J . P

ull t

he o

ther

end

th

roug

h ho

le M

and

pul

l it t

ight

to k

eep

it in

pla

ce .

Cut

an 8

" ye

llow

jum

per

and

wra

p on

e en

d th

roug

h ey

elet

I . P

ull t

he o

ther

end

th

roug

h ho

le M

and

pul

l it t

ight

to k

eep

it in

pla

ce .

Cut

a 3"

yel

low

jum

per

and

wra

p on

e en

d th

roug

h ey

elet

H . P

ull t

he o

ther

end

th

roug

h ho

le G

and

pul

l it t

ight

to k

eep

it in

pla

ce .

Set

the

filt

er c

ap b

oar

d a

sid

eSt

ore

the

filte

r cap

boa

rd so

mew

here

that

it

won

’t be

dis

turb

ed . Y

ou’re

read

y to

turn

yo

ur a

tten

tion

to th

e m

ain

eyel

et b

oard

.

Wra

pp

ing

par

ts o

nto

th

e fi

lter

cap

bo

ard

stew

mac

.com

2

6

©20

19 S

tew

Mac

382812

34

56

78

5152

10 34 54 68 8385

8687

9091

9294

9796

95

584349

503231

93614435 60

986362

45

3611

37

5541

1214

15

8856

89

42

1619

2123

26 9976

7778

8182

7980

29

46 64

39 4748

30

6566

67

53339

846970

71

72

59

57

7374

40

1320

2227

1817

2524

75

104J 600V

104J 600V

473J 600V

250

473J 600V

+25µF

+25µF

stew

mac

.com

27

©

2019

Ste

wM

ac

382812

34

56

78

5152

10 34 54 68 8385

8687

9091

9294

9796

95

584349

503231

93614435 60

986362

45

3611

37

5541

1214

15

8856

89

42

1619

2123

26 9976

7778

8182

7980

29

46 64

39 4748

30

6566

67

53339

846970

71

72

59

57

7374

40

1320

2227

1817

2524

75

104J 600V

104J 600V

473J 600V

250

473J 600V

+25µF

+25µF

The

mai

n ey

elet

boa

rd is

the

larg

est o

f the

th

ree

eyel

et b

oard

s . P

ositi

on it

as s

how

n ab

ove,

with

hol

e 27

in th

e to

p rig

ht a

nd

hole

75

in th

e bo

ttom

left

.

S

TE

P 5

8

Inst

all a

.1μ

F ca

p +

on

e ju

mp

erW

rap

a .1

μF O

rang

e D

rop

cap

betw

een

eyel

ets 2

6 an

d 99

. Thi

s cap

acito

r doe

s not

ha

ve p

olar

ity a

nd c

an b

e in

stal

led

faci

ng

eith

er d

irect

ion .

Cut a

7-1

/2" y

ello

w ju

mpe

r . Tu

rn th

e bo

ard

over

and

wra

p th

is ju

mpe

r th

roug

h th

e bo

ttom

of e

yele

t 26 .

Run

the

othe

r end

of

this

jum

per u

p th

roug

h ho

le 2

5 an

d pu

ll it

tight

so

it st

ays

in p

lace

.

S

TE

P 5

9

Inst

all a

.047

μF

cap

+ o

ne

jum

per

Add

a .0

47μF

Ora

nge

Dro

p ca

pac

itor

be

twee

n ey

elet

s 37

and

99 .

Thi

s ca

p is

no

t pol

ariz

ed a

nd c

an b

e in

stal

led

faci

ng

eith

er d

irect

ion .

Cut

a 7"

yel

low

jum

per .

Turn

the

boa

rd

over

and

wra

p th

is ju

mpe

r th

roug

h th

e bo

ttom

of e

yele

t 37 .

Run

the

othe

r end

of

this

jum

per u

p th

roug

h ho

le 2

4 an

d pu

ll it

tight

so

it st

ays

in p

lace

.

S

TE

P 6

0

Inst

all a

10

0K

res

isto

r +

on

e ju

mp

er

Add

a 1

00K

resi

stor

bet

wee

n ey

elet

s 98

an

d 99

.

Cut a

1-1

/4" y

ello

w ju

mpe

r, fli

p th

e bo

ard

over

, and

add

the

jum

per

behi

nd t

he

boar

d be

twee

n ey

elet

s 63

and

98 .

S

TE

P 6

1

Inst

all a

250

pF

cap

+ o

ne

jum

per

Add

a 2

50pF

silv

er m

ica

cap

betw

een

eyel

ets

45 a

nd 6

3 .

Cut

a 6-

3/4"

yel

low

jum

per

. Tur

n th

e bo

ard

over

and

wra

p th

is ju

mpe

r thr

ough

th

e bo

ttom

of

eyel

et 4

5 . R

un t

he o

ther

en

d of

thi

s ju

mpe

r up

thr

ough

hol

e 24

an

d pu

ll it

tight

so

it st

ays

in p

lace

.

S

TE

P 6

2

Inst

all t

wo

10

0K

res

isto

rsA

dd a

100

K re

sist

or b

etw

een

eyel

ets

62

and

98 .

Ad

d a

not

her

100

K re

sist

or b

etw

een

eyel

ets

62 a

nd 9

7 .

S

TE

P 6

3

Inst

all a

.047

μF

cap

Add

a .0

47μF

Ora

nge

Dro

p ca

p be

twee

n ey

elet

s 23

and

97 .

S

TE

P 6

4

Ad

d t

wo

jum

per

sCu

t a 2

" jum

per a

nd a

dd it

to e

yele

t 97 .

Cut a

2-3

/4" j

umpe

r and

add

it to

eye

let

98 .

Cut

a 10

-1/2

" ye

llow

jum

per .

Turn

the

bo

ard

over

and

wra

p th

is ju

mpe

r thr

ough

th

e bo

ttom

of

eyel

et 2

3 . R

un t

he o

ther

en

d of

thi

s ju

mpe

r up

thr

ough

hol

e 22

an

d pu

ll it

tight

so

it st

ays

in p

lace

.

S

TE

P 6

5

Inst

all a

25

μF

cap

+ a

1.5

K r

esis

tor,

so

lder

ed t

og

eth

erW

rap

the

lead

s fr

om t

he 1

.5K

resi

stor

ar

ou

nd

th

e le

ads

on

th

e 25

μF

50V

capa

cito

r and

sold

er th

em to

geth

er . N

ote

the

pola

rity

of th

e ca

paci

tor .

Inst

all t

his

resi

stor

/cap

acito

r as

sem

bly

betw

een

eyel

ets

21 a

nd 9

6, m

akin

g su

re

the

capa

cito

r’s n

egat

ive

lead

goe

s to

ey

elet

21 .

S

TE

P 6

6

Inst

all a

no

ther

25

μF

cap

+ a

1.5

K

resi

sto

r, s

old

ered

to

get

her

Wra

p th

e le

ads

from

the

1 .5

K re

sist

or

aro

un

d t

he

lead

s o

n t

he

25μ

F 50

V ca

paci

tor a

nd so

lder

them

toge

ther

. Not

e th

e po

larit

y of

the

capa

cito

r .

Inst

all t

his

resi

stor

/cap

acito

r as

sem

bly

betw

een

eyel

ets

21 a

nd 9

5, m

akin

g su

re

the

capa

cito

r’s n

egat

ive

lead

goe

s to

ey

elet

21 .

S

TE

P 6

7

Ad

d t

wo

jum

per

sCu

t a 3

-1/2

" yel

low

jum

per a

nd w

rap

one

end

thro

ugh

eyel

et 9

6 .

Cut

one

3-1/

4" y

ello

w ju

mpe

r an

d w

rap

one

end

thro

ugh

eyel

et 9

5 .

S

TE

P 6

8

Ad

d a

.1μ

F ca

p +

on

e ju

mp

erA

dd a

.1μF

Ora

nge

Dro

p ca

p be

twee

n ey

elet

s 19

and

94 .

Cut

a 10

-3/4

" ye

llow

jum

per .

Turn

the

bo

ard

over

and

wra

p th

is ju

mpe

r thr

ough

th

e bo

ttom

of

eyel

et 1

9 . R

un t

he o

ther

en

d of

thi

s ju

mpe

r up

thr

ough

hol

e 18

an

d pu

ll it

tight

so

it st

ays

in p

lace

.

Wra

pp

ing

par

ts o

nto

th

e m

ain

eye

let

bo

ard

96

21

+

25μ

F

Posi

tive

Neg

ativ

e

21

95

+

25μ

F

Posi

tive

Neg

ativ

e

stew

mac

.com

2

8

©20

19 S

tew

Mac

382812

34

56

78

5152

10 34 54 68 8385

8687

9091

9294

9796

95

584349

503231

93614435 60

986362

45

3611

37

5541

1214

15

8856

89

42

1619

2123

26 9976

7778

8182

7980

29

46 64

39 4748

30

6566

67

53339

846970

71

72

59

57

7374

40

1320

2227

1817

2524

75

473J 600V

250

223J 600V

332J 600V

+25µF

510+

+25µF

104J 600V

stew

mac

.com

29

©

2019

Ste

wM

ac

382812

34

56

78

5152

10 34 54 68 8385

8687

9091

9294

9796

95

584349

503231

93614435 60

986362

45

3611

37

5541

1214

15

8856

89

42

1619

2123

26 9976

7778

8182

7980

29

46 64

39 4748

30

6566

67

53339

846970

71

72

59

57

7374

40

1320

2227

1817

2524

75

473J 600V

250

223J 600V

332J 600V

+25µF

510+

+25µF

104J 600V

S

TE

P 6

9

Inst

all a

.047

μF

cap

+ o

ne

jum

per

Add

a .0

47μF

Ora

nge

Dro

p ca

pac

itor

be

twee

n ey

elet

s 36

and

94 .

Cut

an 1

1-1/

2" y

ello

w ju

mpe

r . Tu

rn t

he

boar

d ov

er a

nd w

rap

this

jum

per t

hrou

gh

the

bott

om o

f ey

elet

36 .

Run

the

oth

er

end

of t

his

jum

per

up t

hrou

gh h

ole

17

and

pull

it tig

ht s

o it

stay

s in

pla

ce .

S

TE

P 7

0

Inst

all a

10

0K

res

isto

r +

on

e ju

mp

erA

dd a

100

K re

sist

or b

etw

een

eyel

ets

93

and

94 .

Cut a

1-1

/4" y

ello

w ju

mpe

r, fli

p th

e bo

ard

over

and

add

the

jum

per

beh

ind

the

boar

d be

twee

n ey

elet

s 61

and

93 .

S

TE

P 7

1

Inst

all a

250

pF

cap

+ o

ne

jum

per

Add

a 2

50pF

cap

bet

wee

n ey

elet

s 44

an

d 61

.

Cut a

9-1

/2" y

ello

w ju

mpe

r . Tu

rn th

e bo

ard

over

and

wra

p th

is ju

mpe

r th

roug

h th

e bo

ttom

of e

yele

t 44 .

Run

the

othe

r end

of

this

jum

per u

p th

roug

h ho

le 1

8 an

d pu

ll it

tight

so

it st

ays

in p

lace

.

S

TE

P 7

2

Inst

all t

wo

10

0K

res

isto

rsA

dd a

100

K re

sist

or b

etw

een

eyel

ets

60

and

93 .

Ad

d a

not

her

100

K re

sist

or b

etw

een

eyel

ets

60 a

nd 9

2 .

S

TE

P 7

3

Inst

all o

ne

jum

per

Cut a

1-1

/2" y

ello

w ju

mpe

r, fli

p th

e bo

ard

over

and

add

the

jum

per

beh

ind

the

boar

d be

twee

n ey

elet

s 35

and

60 .

S

TE

P 7

4

Inst

all t

wo

10

0K

res

isto

rsA

dd a

.022

μF O

rang

e D

rop

cap

betw

een

eyel

ets

92 a

nd 5

8 .

Add

a 5

" yel

low

jum

per t

o ey

elet

93 .

Add

a 3

-1/2

" yel

low

jum

per t

o ey

elet

92 .

S

TE

P 7

5

Inst

all a

50

0p

F ca

p +

1M

res

isto

rA

dd a

500

pF s

ilver

mic

a ca

p be

twee

n ey

elet

s 43

and

58 .

Add

a 1

M r

esis

tor

betw

een

eyel

ets

16

and

43 .

S

TE

P 7

6

Inst

all a

25

μF

cap

+ a

n 8

20Ω

re

sist

or,

so

lder

ed t

og

eth

erW

rap

the

lead

s fr

om t

he 8

20Ω

res

isto

r ar

ou

nd

th

e le

ads

on

th

e 25

μF

50V

capa

cito

r and

sold

er th

em to

geth

er . N

ote

the

pola

rity

of th

e ca

paci

tor .

Inst

all t

his

resi

stor

/cap

acito

r as

sem

bly

betw

een

eyel

ets

16 a

nd 9

1, m

akin

g su

re

the

capa

cito

r’s n

egat

ive

lead

goe

s to

ey

elet

16 .

S

TE

P 7

7

Inst

all a

no

ther

25

μF

cap

+ a

2.2

K

resi

sto

r, s

old

ered

to

get

her

Wra

p th

e le

ads

from

the

2 .2

K re

sist

or

aro

un

d t

he

lead

s o

n t

he

25μ

F 50

V ca

paci

tor a

nd so

lder

them

toge

ther

. Not

e th

e po

larit

y of

the

capa

cito

r .

Inst

all t

his

resi

stor

/cap

acito

r as

sem

bly

betw

een

eyel

ets

16 a

nd 9

0, m

akin

g su

re

the

capa

cito

r’s n

egat

ive

lead

goe

s to

ey

elet

16 .

S

TE

P 7

8

Ad

d t

hre

e ju

mp

ers

Cut a

4-1

/2" y

ello

w ju

mpe

r . Tu

rn th

e bo

ard

over

and

wra

p th

is ju

mpe

r th

roug

h th

e bo

ttom

of e

yele

t 43 .

Run

the

othe

r end

of

this

jum

per u

p th

roug

h ho

le 7

2 an

d pu

ll it

tight

so

it st

ays

in p

lace

.

Add

a 4

" yel

low

jum

per t

o ey

elet

91 .

Add

a 2

-3/4

" yel

low

jum

per t

o ey

elet

90 .

S

TE

P 7

9

Ad

d .0

033

μF

cap

+ o

ne

resi

sto

rA

dd a

.003

3μF

Ora

nge

Dro

p ca

paci

tor

betw

een

eyel

ets

42 a

nd 8

9 .

Add

a 1

00K

resi

stor

bet

wee

n ey

elet

s 56

an

d 89

.

S

TE

P 8

0

Ad

d o

ne

resi

sto

r +

on

e ca

pac

ito

rA

dd a

100

K re

sist

or b

etw

een

eyel

ets

56

and

87 .

Ad

d a

.1μ

F O

ran

ge

Dro

p c

apac

ito

r be

twee

n ey

elet

s 55

and

87 .

91

16

+

25μ

F

Posi

tive

Neg

ativ

e

16

90

+25

μF

Posi

tive

Neg

ativ

e

stew

mac

.com

3

0

©20

19 S

tew

Mac

382812

34

56

78

5152

10 34 54 68 8385

8687

9091

9294

9796

95

584349

503231

93614435 60

986362

45

3611

37

5541

1214

15

8856

89

42

1619

2123

26 9976

7778

8182

7980

29

46 64

39 4748

30

6566

67

53339

846970

71

72

59

57

7374

40

1320

2227

1817

2524

75

10pF

+25µF

+25µF

.01μF .01μF .02μF

stew

mac

.com

3

1

©20

19 S

tew

Mac

382812

34

56

78

5152

10 34 54 68 8385

8687

9091

9294

9796

95

584349

503231

93614435 60

986362

45

3611

37

5541

1214

15

8856

89

42

1619

2123

26 9976

7778

8182

7980

29

46 64

39 4748

30

6566

67

53339

846970

71

72

59

57

7374

40

1320

2227

1817

2524

75

10pF

+25µF

+25µF

.01μF .01μF .02μF

S

TE

P 8

1

Ad

d t

wo

jum

per

sCu

t a

9" y

ello

w ju

mpe

r . Tu

rn t

he b

oard

ov

er a

nd w

rap

this

jum

per

thro

ugh

the

bott

om o

f eye

let 4

2 . R

un th

e ot

her e

nd o

f th

is ju

mpe

r up

thro

ugh

hole

13

and

pull

it tig

ht s

o it

stay

s in

pla

ce .

Add

a 2

-1/2

" yel

low

jum

per t

o ey

elet

89 .

S

TE

P 8

2

Ad

d t

wo

jum

per

sCu

t a 6

-1/4

" yel

low

jum

per .

Turn

the

boar

d ov

er a

nd w

rap

this

jum

per

thro

ugh

the

bott

om o

f eye

let

55 . R

un t

he o

ther

end

of

thi

s ju

mpe

r up

thr

ough

hol

e 13

and

pu

ll it

tight

so

it st

ays

in p

lace

.

Add

a 2

-1/4

" yel

low

jum

per t

o ey

elet

87 .

S

TE

P 8

3

Ad

d 1

0p

F ca

p +

on

e re

sist

or

Add

a 1

0pF

capa

cito

r and

a 3

.3M

resi

stor

be

twee

n ey

elet

s 15

and

41 .

S

TE

P 8

4

Ad

d t

wo

res

isto

rsA

dd a

470

K re

sist

or b

etw

een

eyel

ets

14

and

41 .

Add

a 2

20K

resi

stor

bet

wee

n ey

elet

s 12

an

d 41

.

S

TE

P 8

5

Inst

all a

25

μF

cap

+ a

n 8

20Ω

re

sist

or,

so

lder

ed t

og

eth

erW

rap

the

lead

s fr

om t

he 8

20Ω

res

isto

r ar

ou

nd

th

e le

ads

on

th

e 25

μF

50V

capa

cito

r and

sold

er th

em to

geth

er . N

ote

the

pola

rity

of th

e ca

paci

tor .

Inst

all t

his

asse

mbl

y be

twee

n ey

elet

s 12

and

86,

mak

ing

sure

the

cap

acito

r’s

nega

tive

lead

goe

s to

eye

let 1

2 .

S

TE

P 8

6

Inst

all a

no

ther

25

μF

cap

+ a

2.7

K

resi

sto

r, s

old

ered

to

get

her

Wra

p th

e le

ads

from

the

2 .7

K re

sist

or

aro

un

d t

he

lead

s o

n t

he

25μ

F 50

V ca

paci

tor a

nd so

lder

them

toge

ther

. Not

e th

e po

larit

y of

the

capa

cito

r .

Inst

all t

his

asse

mbl

y be

twee

n ey

elet

s 12

and

85,

mak

ing

sure

the

cap

acito

r’s

nega

tive

lead

goe

s to

eye

let 1

2 .

S

TE

P 8

7

Ad

d fo

ur

jum

per

sCu

t a 3

-1/2

" yel

low

jum

per .

Turn

the

boar

d ov

er a

nd w

rap

this

jum

per

thro

ugh

the

bott

om o

f eye

let

41 . R

un t

he o

ther

end

of

thi

s ju

mpe

r up

thr

ough

hol

e 70

and

pu

ll it

tight

so

it st

ays

in p

lace

.

Cut a

9-1

/2" y

ello

w ju

mpe

r . Tu

rn th

e bo

ard

over

and

wra

p th

is ju

mpe

r th

roug

h th

e bo

ttom

of e

yele

t 14

. Run

the

oth

er e

nd

of t

his

jum

per

up t

hrou

gh h

ole

13 a

nd

pull

it tig

ht s

o it

stay

s in

pla

ce .

Add

a 1

-3/4

" yel

low

jum

per t

o ey

elet

86 .

Add

a 3

" yel

low

jum

per t

o ey

elet

85 .

S

TE

P 8

8

Ad

d t

hre

e re

sist

ors

Add

a 1

M r

esis

tor

betw

een

eyel

ets

11

and

54 .

Add

a 1

M r

esis

tor

betw

een

eyel

ets

11

and

34 .

Add

a 2

.2M

res

isto

r be

twee

n ey

elet

s 10

an

d 11

.

S

TE

P 8

9

Ad

d t

hre

e ca

pac

ito

rs

Add

a .0

1μF

cera

mic

dis

k ca

p be

twee

n ey

elet

s 34

and

54 .

Add

a .0

1μF

cera

mic

dis

k ca

p be

twee

n ey

elet

s 54

and

68 .

Add

a .0

2μF

cera

mic

dis

k ca

p be

twee

n ey

elet

s 68

and

83 .

S

TE

P 9

0

Ad

d fo

ur

jum

per

sCu

t a 6

-1/2

" yel

low

jum

per .

Turn

the

boar

d ov

er a

nd w

rap

this

jum

per

thro

ugh

the

bott

om o

f eye

let 1

1 . R

un th

e ot

her e

nd o

f th

is ju

mpe

r up

thro

ugh

hole

84

and

pull

it tig

ht s

o it

stay

s in

pla

ce .

Cut a

4-1

/2" y

ello

w ju

mpe

r . W

rap

one

end

thro

ugh

eyel

et 3

4 an

d ru

n th

e ot

her e

nd

dow

n th

roug

h ho

le 4

0 . F

lip t

he b

oard

ov

er, p

ull t

his

jum

per

back

up

thro

ugh

hole

84

and

pull

it tig

ht to

kee

p it

in p

lace

.

Cut

a 3"

yel

low

jum

per .

Turn

the

boa

rd

over

and

wra

p th

is ju

mpe

r th

roug

h th

e bo

ttom

of e

yele

t 54 .

Run

the

othe

r end

of

this

jum

per u

p th

roug

h ho

le 6

9 an

d pu

ll it

tight

so

it st

ays

in p

lace

.

Add

a 2

-1/2

" yel

low

jum

per t

o ey

elet

83 .

86

12

+25

μF

Posi

tive

Neg

ativ

e

12

85

+

25μ

F

Posi

tive

Neg

ativ

e

stew

mac

.com

3

2

©20

19 S

tew

Mac

67

8

5152

10 34

54 68 8385

8687

9091

9294

9796

95

584349

503231

93614435 60

986362

45

3611

37

5541

1214

15

8856

89

42

1619

2123

26 9981

8279

80

675333

9

84

6970

7172

59

57

7374

40

1320

2227

1817

2524

382812

34

5

7677

78

29

46 64

39 4748

30

6566

75

+25µF

102J 1119

stew

mac

.com

3

3

©20

19 S

tew

Mac

67

8

5152

10 34

54 68 8385

8687

9091

9294

9796

95

584349

503231

93614435 60

986362

45

3611

37

5541

1214

15

8856

89

42

1619

2123

26 9981

8279

80

675333

9

84

6970

7172

59

57

7374

40

1320

2227

1817

2524

382812

34

5

7677

78

29

46 64

39 4748

30

6566

75

+25µF

102J 1119

S

TE

P 9

1

Ad

d t

wo

jum

per

sCu

t a 1

0" y

ello

w ju

mpe

r . W

rap

one

end

thro

ugh

eyel

et 6

8 an

d ru

n th

e ot

her

end

dow

n th

roug

h ho

le 5

3 . F

lip t

he

boar

d ov

er, p

ull t

his

jum

per

back

up

thro

ugh

hole

33

and

pull

it tig

ht to

kee

p it

in p

lace

.

Cu

t an

9-1

/2"

yello

w j

um

per

. Tu

rn

the

boar

d ov

er a

nd w

rap

this

jum

per

thro

ugh

the

bott

om o

f ey

elet

10 .

Run

th

e ot

her e

nd o

f thi

s jum

per u

p th

roug

h ho

le 9

and

pul

l it ti

ght s

o it

stay

s in

plac

e .

S

TE

P 9

2

Ad

d t

hre

e re

sist

ors

Add

a 2

20K

resi

stor

bet

wee

n ey

elet

s 82

and

83 .

Add

a 1

00K

resi

stor

bet

wee

n ey

elet

s 52

and

82 .

Add

a 1

0M re

sist

or b

etw

een

eyel

ets

51

and

82 .

S

TE

P 9

3

Inst

all t

he

op

toco

up

ler

Orie

nt th

e op

toco

uple

r as

show

n in

the

wiri

ng d

iagr

am, w

ith t

he s

ide

with

the

do

t bet

wee

n ey

elet

s 51

and

52 . W

rap

one

lead

of t

he d

ot s

ide

of t

he o

ptoc

oupl

er

thro

ugh

eyel

et 5

1 an

d th

e ot

her l

ead

from

th

at s

ide

thro

ugh

eyel

et 5

2 . W

rap

the

othe

r end

's le

ads t

hrou

gh e

yele

ts 7

and

8 .

This

lit

tle

devi

ce is

wha

t co

ntro

ls t

he

vibr

ato

for t

he a

mp .

The

end

with

the

dot

has

an L

ED a

nd th

e ot

her e

nd is

a li

ght-

depe

nden

t re

sist

or . T

he s

peed

con

trol

de

term

ines

the

fre

quen

cy a

t w

hich

the

LE

D f

lash

es, a

nd t

he in

tens

ity

cont

rol

det

erm

ines

how

muc

h of

th

e gu

itar

si

gnal

is a

ffect

ed b

y th

e lig

ht-d

epen

dent

re

sist

or .

S

TE

P 9

4

Ad

d t

hre

e ju

mp

ers

Cut a

10"

yel

low

jum

per .

Turn

the

boar

d ov

er a

nd w

rap

this

jum

per

thro

ugh

the

bott

om o

f eye

let 8

. Run

the

othe

r end

of

this

jum

per u

p th

roug

h ho

le 9

and

pul

l it

tight

so

it st

ays

in p

lace

.

Cut a

3-1

/4" y

ello

w ju

mpe

r . Tu

rn th

e bo

ard

over

and

wra

p th

is ju

mpe

r th

roug

h th

e bo

ttom

of e

yele

t 51

. Run

the

oth

er e

nd

of t

his

jum

per

up t

hrou

gh h

ole

67 a

nd

pull

it tig

ht s

o it

stay

s in

pla

ce .

Add

a 1

/2"

bare

wire

bet

wee

n ey

elet

s 6

and

7 .

S

TE

P 9

5

Inst

all a

no

ther

25

μF

cap

+ a

10

0K

re

sist

or,

so

lder

ed t

og

eth

erW

rap

the

lead

s fr

om t

he 1

00K

resi

stor

ar

ou

nd

th

e le

ads

on

th

e 25

μF

50V

capa

cito

r and

sold

er th

em to

geth

er . N

ote

the

pola

rity

of th

e ca

paci

tor .

Inst

all t

his

asse

mbl

y be

twee

n ey

elet

s 6

and

81, m

akin

g su

re t

he c

apac

itor’s

ne

gativ

e le

ad g

oes

to e

yele

t 6 .

S

TE

P 9

6

Ad

d t

hre

e re

sist

ors

Add

a 4

7Ω r

esis

tor

betw

een

eyel

ets

5 an

d 6 .

Add

a 2

20K

resi

stor

bet

wee

n ey

elet

s 32

an

d 50

.

Add

a 2

20K

resi

stor

bet

wee

n ey

elet

s 31

an

d 50

.

S

TE

P 9

7

Inst

all t

hre

e re

sist

ors

+ o

ne

cap

acit

or

Add

a 1

M r

esis

tor

betw

een

eyel

ets

49

and

80 .

Add

a 4

70Ω

resi

stor

bet

wee

n ey

elet

s 49

an

d 79

.

Add

ano

ther

1M

resi

stor

bet

wee

n ey

elet

s 49

and

78 .

Add

a .0

01μF

Ora

nge

Dro

p ca

p be

twee

n ey

elet

s 50

and

80 .

81

6

+

25μ

F

Posi

tive

Neg

ativ

e

stew

mac

.com

3

4

©20

19 S

tew

Mac

38

28

12

34

56

78

5152

10 34

54 68 8385

8687

9091

9294

9796

95

584349

503231

93614435 60

986362

45

3611

37

5541

1214

15

8856

89

42

1619

2123

26 9976

7778

8182

7980

29

46 64

39 4748

30

6566

675333

9

84

6970

7172

59

57

7374

40

1320

2227

1817

2524

75

104J 600V

104J 600V

104J 600V

stew

mac

.com

3

5

©20

19 S

tew

Mac

38

28

12

34

56

78

5152

10 34

54 68 8385

8687

9091

9294

9796

95

584349

503231

93614435 60

986362

45

3611

37

5541

1214

15

8856

89

42

1619

2123

26 9976

7778

8182

7980

29

46 64

39 4748

30

6566

675333

9

84

6970

7172

59

57

7374

40

1320

2227

1817

2524

75

104J 600V

104J 600V

104J 600V

ST

EP

98

Ad

d t

wo

res

isto

rs +

on

e ca

pac

ito

rA

dd a

22K

resi

stor

bet

wee

n ey

elet

5 a

nd

49 .

Add

an

820Ω

res

isto

r be

twee

n ey

elet

s 5

and

48 .

Add

a .1

μF O

rang

e D

rop

cap

betw

een

eyel

ets

5 an

d 78

.

S

TE

P 9

9

Ad

d t

hre

e ju

mp

ers

Add

a 2

-1/4

" yel

low

jum

per t

o ey

elet

81 .

Add

a 3

" yel

low

jum

per t

o ey

elet

80 .

Cut a

n 11

" yel

low

jum

per .

Turn

the

boar

d ov

er a

nd w

rap

this

jum

per

thro

ugh

the

bott

om o

f eye

let

32 . R

un t

he o

ther

end

of

this

jum

per u

p th

roug

h ho

le 9

and

pul

l it

tight

so

it st

ays

in p

lace

.

S

TE

P 1

00

Ad

d t

hre

e m

ore

jum

per

sA

dd a

2" y

ello

w ju

mpe

r to

eyel

et 7

9 .

Add

a 2

" yel

low

jum

per t

o ey

elet

78 .

Cut

an 8

-1/2

" ye

llow

jum

per .

Turn

the

bo

ard

over

and

wra

p th

is ju

mpe

r thr

ough

th

e bo

ttom

of e

yele

t 48

. Run

the

oth

er

end

of t

his

jum

per

up t

hrou

gh h

ole

66

and

pull

it tig

ht s

o it

stay

s in

pla

ce .

S

TE

P 1

01

Ad

d fo

ur

resi

sto

rsA

dd a

n 82

K re

sist

or b

etw

een

eyel

ets

47

and

77 .

Add

a 1

00K

resi

stor

bet

wee

n ey

elet

s 47

an

d 76

.

Add

a 2

20K

resi

stor

bet

wee

n ey

elet

s 3

and

39 .

Add

a 2

20K

resi

stor

bet

wee

n ey

elet

s 4

and

39 .

S

TE

P 1

02

Ad

d t

wo

.1μ

F ca

ps

Add

a .1

μF O

rang

e D

rop

cap

betw

een

eyel

ets

4 an

d 77

.

Ad

d a

not

her

.1μ

F O

ran

ge

Dro

p c

ap

betw

een

eyel

ets

3 an

d 76

.

S

TE

P 1

03

Ad

d fo

ur

jum

per

sA

dd a

4" y

ello

w ju

mpe

r to

eyel

et 7

7 .

Add

a 3

-1/4

" yel

low

jum

per t

o ey

elet

76 .

Cut a

6-1

/2" y

ello

w ju

mpe

r . Tu

rn th

e bo

ard

over

and

wra

p th

is ju

mpe

r th

roug

h th

e bo

ttom

of e

yele

t 4 . R

un th

e ot

her e

nd o

f th

is ju

mpe

r up

thro

ugh

hole

65

and

pull

it tig

ht s

o it

stay

s in

pla

ce .

Cut

a 7"

yel

low

jum

per .

Turn

the

boa

rd

over

and

wra

p th

is ju

mpe

r th

roug

h th

e bo

ttom

of e

yele

t 3 . R

un th

e ot

her e

nd o

f th

is ju

mpe

r up

thro

ugh

hole

65

and

pull

it tig

ht s

o it

stay

s in

pla

ce .

S

TE

P 1

04

Ad

d t

hre

e ju

mp

ers

Cut a

3-3

/4" y

ello

w ju

mpe

r . Tu

rn th

e bo

ard

over

and

wra

p th

is ju

mpe

r th

roug

h th

e bo

ttom

of e

yele

t 39

. Run

the

oth

er e

nd

of t

his

jum

per

up t

hrou

gh h

ole

30 a

nd

pull

it tig

ht s

o it

stay

s in

pla

ce .

Add

a 3

/4"

bare

wire

bet

wee

n ey

elet

s 2

and

29 .

Add

ano

ther

3/4

" b

are

wir

e b

etw

een

eyel

ets

46 a

nd 6

4 .

S

TE

P 1

05

Ad

d fo

ur

mo

re ju

mp

ers

Cut a

7-1

/2" y

ello

w ju

mpe

r . Tu

rn th

e bo

ard

over

and

wra

p th

is ju

mpe

r th

roug

h th

e bo

ttom

of e

yele

t 64 .

Run

the

othe

r end

of

this

jum

per u

p th

roug

h ho

le 7

5 an

d pu

ll it

tight

so

it st

ays

in p

lace

.

Cut

a 4"

yel

low

jum

per .

Turn

the

boa

rd

over

and

wra

p th

is ju

mpe

r th

roug

h th

e bo

ttom

of e

yele

t 29

. Run

the

oth

er e

nd

of t

his

jum

per

up t

hrou

gh h

ole

38 a

nd

pull

it tig

ht s

o it

stay

s in

pla

ce .

Cut a

7-3

/4" y

ello

w ju

mpe

r . Tu

rn th

e bo

ard

over

and

wra

p th

is ju

mpe

r th

roug

h th

e bo

ttom

of e

yele

t 1 . R

un th

e ot

her e

nd o

f th

is ju

mpe

r up

thro

ugh

hole

28

and

pull

it tig

ht s

o it

stay

s in

pla

ce .

Cut

anot

her

7-3/

4" y

ello

w ju

mpe

r . Tu

rn

the

boar

d ov

er a

nd a

lso

wra

p th

is ju

mpe

r th

roug

h th

e bo

ttom

of e

yele

t 1 . R

un th

e ot

her e

nd o

f thi

s jum

per u

p th

roug

h ho

le

28 a

nd p

ull i

t tig

ht s

o it

stay

s in

pla

ce .

Your

min

d is

not

pla

ying

tric

ks o

n yo

u he

re; y

ou r

eally

nee

d tw

o ju

mp

ers

of

the

sam

e le

ngth

com

ing

from

eye

let

1 th

roug

h ho

le 2

8 .

stew

mac

.com

3

6

©20

19 S

tew

Mac

38

28

12

34

56

78

5152

10 34

54 68 8385

8687

9091

9294

9796

95

584349

503231

93614435 60

986362

45

3611

37

5541

1214

15

8856

89

42

1619

2123

26 9976

7778

8182

7980

29

46 64

39 4748

30

6566

675333

9

84

6970

7172

59

57

7374

40

1320

2227

1817

2524

75

stew

mac

.com

3

7

©20

19 S

tew

Mac

38

28

12

34

56

78

5152

10 34

54 68 8385

8687

9091

9294

9796

95

584349

503231

93614435 60

986362

45

3611

37

5541

1214

15

8856

89

42

1619

2123

26 9976

7778

8182

7980

29

46 64

39 4748

30

6566

675333

9

84

6970

7172

59

57

7374

40

1320

2227

1817

2524

75 S

TE

P 1

06

Two

flyi

ng

jum

per

sFl

ying

jum

pers

are

wire

s th

at tr

avel

ove

r th

e bo

ard,

jum

ping

fro

m o

ne e

yele

t to

an

othe

r . Th

ese

are

very

com

mon

in cl

assi

c po

int-

to-p

oint

circ

uits

.

The

first

flyi

ng ju

mpe

r is

the

one

you'

ve

inst

alle

d co

min

g fr

om h

ole

22 . I

t ne

eds

to ru

n to

the

left

, alo

ng th

e to

p ed

ge o

f th

e ey

elet

boa

rd u

ntil

it ge

ts to

hol

e 13

. Th

ere

it w

ill b

e tw

iste

d in

line

with

the

be

hind

-the

-boa

rd le

ad f

rom

eye

let

55,

com

ing

thro

ugh

hole

13 .

S

TE

P 1

07

Twis

tin

g fl

yin

g ju

mp

ers

Care

fully

twis

t the

se tw

o fly

ing

jum

pers

to

geth

er to

war

d th

e le

ft si

de o

f the

boa

rd

whi

le m

akin

g su

re n

ot t

o di

stur

b th

eir

wra

pped

con

nect

ions

on

the

eyel

ets .

Yo

u w

ant

the

lead

s to

be

up a

nd a

way

fr

om c

ompo

nent

s . S

top

twis

ting

them

to

geth

er o

nce

you

are

abov

e ey

elet

s 31

an

d 32

. The

y w

ill b

e co

nnec

ting

to th

ese

eyel

ets .

S

TE

P 1

08

Inst

alli

ng

flyi

ng

jum

per

sU

se a

mul

timet

er to

find

the

flyin

g ju

mpe

r w

ith co

ntin

uity

to e

yele

t 23 .

Wra

p th

e fr

ee

end

of th

at ju

mpe

r to

eyel

et 3

1 .

The

othe

r fl

ying

jum

per

sho

uld

have

co

ntin

uity

to e

yele

t 55 .

Wra

p th

e fr

ee e

nd

of th

is ju

mpe

r to

eyel

et 3

2 .

S

TE

P 1

09

Ad

d t

hre

e b

ehin

d-t

he-

bo

ard

ju

mp

ers

Cut a

2-3

/4" y

ello

w ju

mpe

r . Tu

rn th

e bo

ard

over

and

wra

p th

is ju

mpe

r th

roug

h th

e bo

ttom

of e

yele

t 35 .

Wra

p th

e ot

her e

nd

of t

his

jum

per

thro

ugh

the

bott

om o

f ey

elet

62 .

Cut a

3-1

/4" y

ello

w ju

mpe

r . Tu

rn th

e bo

ard

over

and

wra

p th

is ju

mpe

r th

roug

h th

e bo

ttom

of e

yele

t 35 .

Wra

p th

e ot

her e

nd

of t

his

jum

per

thro

ugh

the

bott

om o

f ey

elet

56 .

Cut a

2-1

/4" y

ello

w ju

mpe

r . Tu

rn th

e bo

ard

over

and

wra

p th

is ju

mpe

r th

roug

h th

e bo

ttom

of e

yele

t 15 .

Wra

p th

e ot

her e

nd

of t

his

jum

per

thro

ugh

the

bott

om o

f ey

elet

58 .

S

TE

P 1

10

Ad

d fo

ur

jum

per

sCu

t a

6" y

ello

w j

ump

er a

nd a

n 8-

1/4"

ye

llow

jum

per

. Mar

k th

e en

ds o

f th

e 6"

wire

with

a b

lack

mar

ker .

Pass

bot

h w

ires d

own

thro

ugh

hole

27

and

back

up

thro

ugh

hole

74 .

Cut t

wo

11" y

ello

w ju

mpe

rs a

nd m

ark

the

ends

of o

ne w

ith a

bla

ck m

arke

r . Pa

ss b

oth

wire

s dow

n th

roug

h ho

le 2

0 an

d ba

ck u

p th

roug

h ho

le 7

3 .

S

TE

P 1

11

Ad

d fo

ur

gro

un

d ju

mp

ers

Cut f

our 3

" gre

en ju

mpe

rs .

Add

the

first

to e

yele

t 21 .

Add

the

seco

nd to

eye

let 1

6 .

Add

the

third

to e

yele

t 12 .

Add

the

four

th to

eye

let 6

.

Sto

p a

nd

rev

iew

Now

all

the

com

pone

nts a

nd w

ires a

re o

n th

e ey

elet

boa

rd . S

top

and

take

a b

reak

so

you

’ll h

ave

fres

h ey

es t

o re

view

you

r w

ork

befo

re s

olde

ring .

Mak

e su

re y

ou’v

e fo

llow

ed e

ach

step

co

rrec

tly . I

t w

ould

be

surp

risin

g to

find

no

mis

take

s at

thi

s po

int,

and

it’s

muc

h le

ss w

ork

to fi

nd a

nd fi

x th

em n

ow ra

ther

th

an a

fter

sol

derin

g!

As

you’

re c

heck

ing

your

wor

k, m

ake

sure

all

your

con

nect

ions

are

tigh

t . D

on’t

coun

t on

sol

der

to “

glue

” yo

ur jo

ints

—

mak

e th

em m

echa

nica

lly t

ight

bef

ore

sold

er is

eve

r app

lied .PA

USE

stew

mac

.com

3

8

©20

19 S

tew

Mac

NO

RMA

LV

OLU

ME

TREB

LEB

ASS

VO

LUM

ETR

EBLE

BA

SSRE

VER

BPI

LOT

SPEE

DIN

TEN

SITY

VIB

RAT

O

21

21

REV

ERB

INPU

TRE

VER

B

OU

TPU

TRE

VER

B

PED

AL

VIB

RAT

OPE

DA

LEX

T. S

PKR

SPEA

KER

STA

ND

BYPO

WER

FUSE

GRO

UN

D

V1

12A

X7

V2

12A

X7

V3

12A

T7V

412

AX

7V

512

AX

7V

612

AT7

V7

6V6

V8

6V6

V9

5AR4

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

4 3

21

87

65

4 3

21

87

65

4 3

21

87

65

Insu

lato

rB

oard

Insu

lato

rB

oard

382812

34

56

78

5152

10 34 54 68 8385

8687

9091

9294

9796

95

584349

503231

93614435 60

986362

45

3611

37

5541

1214

15

8856

89

42

1619

2123

26 9976

7778

8182

7980

29

46 64

39 4748

30

6566

67

53339

846970

71

72

59

57

7374

40

1320

2227

1817

2524

75

AB

CD

FE

104J 600V

104J 600V

473J 600V

473J 600V

+25µF

+25µF

473J 600V

250

222J 600V

332J 600V

+25µF

510+

+25µF

+25µF

102J 1119

10pF

+25µF

+25µF

104J 600V

104J 600V

.01μF .01μF .02μF

104J 600V

104J 600V

250

+

25µ

F

stew

mac

.com

3

9

©20

19 S

tew

Mac

S

TE

P 1

12

Sold

er t

he

com

po

nen

ts

on

th

e ey

elet

bo

ard

sN

ow th

at th

e co

mpo

nent

s an

d ju

mpe

rs

are

on t

he b

oard

s an

d do

uble

-che

cked

fo

r cor

rect

pla

cem

ent,

its ti

me

to s

et th

e co

nnec

tions

with

sold

er . R

evie

w "T

ips f

or

grea

t sol

derin

g" o

n pa

ge 1

1 .

Aft

er a

ll th

e jo

ints

are

sol

dere

d, c

lip th

e ex

cess

lead

s on

the

fron

t and

bac

k of

the

boar

ds . T

rimm

ing

the

exce

ss is

impo

rtan

t to

avo

id a

sho

rt in

you

r circ

uit .

Chec

k al

l you

r so

lder

join

ts t

o se

e th

at

they

’re s

hiny

and

to m

ake

sure

that

you

ha

ven’

t mis

sed

one .

S

TE

P 1

13

Inst

all a

ll t

hre

e ey

elet

bo

ard

s,

bac

ked

by

thei

r in

sula

tor

bo

ard

sBe

fore

inst

allin

g th

e m

ain

eyel

et b

oard

an

d in

sula

tor b

oard

in th

e ch

assi

s, m

ake

sure

you

hav

e en

ough

len

gth

on t

he

unso

lder

ed j

ump

ers

com

ing

thro

ugh

hole

s 27

and

74,

and

hol

es 2

0 an

d 73

, to

reac

h th

eir

com

pone

nts .

The

bes

t w

ay

to d

o th

is is

to

lay

the

eyel

et b

oard

on

the

floor

of

the

chas

sis

whe

re it

will

be

mou

nted

and

adj

ust t

hese

jum

pers

unt

il th

ey re

ach

thei

r com

pone

nts .

To in

stal

l th

e m

ain

eyel

et b

oard

, fir

st

lay

the

mai

n in

sula

tion

boa

rd o

n th

e bo

ttom

of

the

chas

sis,

alig

ning

it w

ith

the

mou

ntin

g ho

les .

Run

a 6

-32

x 1/

2"

mac

hine

scre

w th

roug

h th

e ey

elet

boa

rd,

the

insu

latio

n bo

ard

and

thro

ugh

the

chas

sis .

Sec

ure

it w

ith a

lock

nut

on t

he

outs

ide

of th

e ch

assi

s . D

o th

e sa

me

with

th

e se

cond

bol

t .

Inst

all t

he b

ias b

oard

in th

e sa

me

man

ner:

insu

latio

n bo

ard

dow

n fir

st, e

yele

t boa

rd

on t

op, m

ount

ed w

ith t

wo

sets

of

6-32

ha

rdw

are .

To i

nsta

ll th

e fi

lter

cap

eye

let

boa

rd,

flip

the

chas

sis

over

. Run

the

jum

pers

th

roug

h th

e ey

elet

boa

rd a

nd t

hrou

gh

the

insu

latio

n bo

ard

and

then

alig

n th

e fil

ter c

ap b

oard

with

the

grom

met

s an

d pa

ss th

e ju

mpe

rs th

roug

h th

e gr

omm

ets .

This

filte

r ca

p ey

elet

boa

rd w

ill n

ot b

e m

ount

ed w

ith s

crew

s bu

t rat

her h

eld

on

by th

e ju

mpe

r wire

s . O

nce

you

have

the

boar

ds f

lush

with

the

bac

k si

de o

f th

e ch

assi

s, b

end

the

jum

pers

ove

r ins

ide

the

chas

sis t

o ke

ep th

e bo

ard

tight

to th

e ba

ck

of th

e ch

assi

s .

Insu

lato

r boa

rd

G

NH

OI

PJ

RK

SLM

Q

16μF

16μF

16μF

16μF

16μF

stew

mac

.com

4

0

©20

19 S

tew

Mac

NO

RMA

LV

OLU

ME

TREB

LEB

ASS

VO

LUM

ETR

EBLE

BA

SSRE

VER

BPI

LOT

SPEE

DIN

TEN

SITY

VIB

RAT

O

21

21

REV

ERB

INPU

TRE

VER

B

OU

TPU

TRE

VER

B

PED

AL

VIB

RAT

OPE

DA

LEX

T. S

PKR

SPEA

KER

STA

ND

BYPO

WER

FUSE

GRO

UN

D

V1

12A

X7

V2

12A

X7

V3

12A

T7V

412

AX

7V

512

AX

7V

612

AT7

V7

6V6

V8

6V6

V9

5AR4A

BC

D

FE

4 3

21

87

65

4 3

21

87

65

4 3

21

87

65

250KA

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

250KA

382812

34

56

78

5152

10 34 54 68 8385

8687

9091

9294

9796

95

584349

503231

93614435 60

986362

45

3611

37

5541

1214

15

8856

89

42

1619

2123

26 9976

7778

8182

7980

29

46 64

39 4748

30

6566

67

53339

846970

71

72

59

57

7374

40

1320

2227

1817

2524

75

stew

mac

.com

4

1

©20

19 S

tew

Mac

S

TE

P 1

14

Sold

er t

he

filt

er c

ap b

oar

d ju

mp

ers

Pull

the

two

jum

pers

com

ing

thro

ugh

the

grom

met

ed h

ole

betw

een

tube

sock

et V

4 an

d tu

be s

ocke

t V5

until

they

are

tigh

t .

Sold

er o

ne o

f the

se ju

mpe

rs to

eye

let 8

2 .

Sold

er th

e ot

her j

umpe

r to

eyel

et 8

8 .

S

TE

P 1

15

Sold

er t

he

filt

er c

ap b

oar

d ju

mp

ers,

co

nt.

Pull

the

two

jum

pers

com

ing

thro

ugh

the

grom

met

ed h

ole

behi

nd th

e no

rmal

ch

anne

l bas

s po

t unt

il th

ey a

re ti

ght .

Sold

er th

e ye

llow

jum

per t

o ey

elet

35 .

Sold

er t

he g

reen

jum

per

to t

he b

ack

of

the

norm

al c

hann

el b

ass

pot .

S

TE

P 1

16

Sold

er t

he

filt

er c

ap b

oar

d ju

mp

ers,

co

nt.

Sold

er fi

lter c

ap b

oard

jum

pers

, con

t .

Pull

the

four

jum

pers

com

ing

thro

ugh

the

grom

met

ed h

ole

behi

nd th

e vi

brat

o ch

anne

l tre

ble

pot u

ntil

they

are

tigh

t .

Sold

er t

he g

reen

jum

per

to t

he b

ack

of

the

vibr

ato

chan

nel t

rebl

e po

t .

Sold

er t

he j

ump

er w

ith

cont

inui

ty t

o ey

elet

L to

eye

let 1

.

Sold

er t

he j

ump

er w

ith

cont

inui

ty t

o ey

elet

J to

eye

let 2

.

Sold

er t

he j

ump

er w

ith

cont

inui

ty t

o ey

elet

I to

eye

let 4

7 . Y

ou w

ill h

ave

to ru

n th

is ju

mpe

r und

erne

ath

the

.1μF

Ora

nge

Dro

p ca

p in

stal

led

betw

een

eyel

ets

4 an

d 77

.

S

TE

P 1

17

Sold

er t

ub

e so

cket

V9

Wra

p on

e of

the

7-3

/4"

yello

w ju

mpe

rs

from

hol

e 28

to p

in 8

on

tube

soc

ket V

9 al

ong

with

the

yello

w p

ower

tran

sfor

mer

le

ad .

Sold

er a

ll co

nnec

tions

to th

is so

cket

(five

w

ires)

and

trim

the

exce

ss w

ire e

nds .

S

TE

P 1

18

Sold

er t

ub

e so

cket

V8

Test

the

two

jum

pers

com

ing

from

hol

e 65

to

iden

tify

the

one

with

con

tinui

ty

to e

yele

t 3 . W

rap

this

jum

per t

o pi

n 1

of

tube

soc

ket V

8 .

Sold

er a

ll co

nnec

tions

to th

is so

cket

(five

w

ires,

four

resi

stor

lead

s) a

nd tr

im e

xces

s w

ire e

nds .

S

TE

P 1

19

Sold

er t

ub

e so

cket

V7

Test

the

rem

aini

ng ju

mpe

r com

ing

from

ho

le 6

5 to

mak

e su

re it

has

con

tinui

ty

to e

yele

t 4 . W

rap

this

jum

per t

o pi

n 1

of

tube

soc

ket V

7 .

Wra

p th

e ye

llow

jum

per f

rom

hol

e 38

to

pin

6 of

tub

e so

cket

V7

alon

g w

ith t

he

resi

stor

lead

in p

lace

.

Sold

er a

ll co

nnec

tions

to th

is so

cket

(five

w

ires,

four

resi

stor

lead

s) a

nd tr

im e

xces

s w

ire e

nds .

S

TE

P 1

20

Sold

er t

ub

e so

cket

V6

Wra

p th

e ju

mpe

r fro

m e

yele

t 76

to p

in 6

of

the

V6 tu

be s

ocke

t .

Wra

p th

e ju

mpe

r fro

m e

yele

t 77

to p

in 1

of

the

V6 tu

be s

ocke

t .

Wra

p th

e ju

mpe

r fro

m e

yele

t 78

to p

in 7

of

the

V6 tu

be s

ocke

t .

Wra

p th

e ju

mpe

r fr

om e

yele

t 79

to

pin

8 of

the

V6

tube

soc

ket

alon

g w

ith t

he

jum

per a

lread

y in

pla

ce .

Wra

p th

e ju

mpe

r fro

m e

yele

t 80

to p

in 2

of

the

V6 tu

be s

ocke

t .

Sold

er th

e co

nnec

tions

to th

is so

cket

(six

w

ires)

and

trim

the

exce

ss w

ire e

nds .

stew

mac

.com

4

2

©20

19 S

tew

Mac

NO

RMA

LV

OLU

ME

TREB

LEB

ASS

VO

LUM

ETR

EBLE

BA

SSRE

VER

BPI

LOT

SPEE

DIN

TEN

SITY

VIB

RAT

O

21

21

REV

ERB

INPU

TRE

VER

B

OU

TPU

TRE

VER

B

PED

AL

VIB

RAT

OPE

DA

LEX

T. S

PKR

SPEA

KER

STA

ND

BYPO

WER

FUSE

GRO

UN

D

V1

12A

X7

V2

12A

X7

V3

12A

T7V

412

AX

7V

512

AX

7V

612

AT7

V7

6V6

V8

6V6

V9

5AR4A

BC

D

FE

6

4321

98 7 5

4 3

21

87

65

4 3

21

87

65

4 3

21

87

65

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

382812

34

56

78

5152

10 34 54 68 8385

8687

9091

9294

9796

95

584349

503231

93614435 60

986362

45

3611

37

5541

1214

15

8856

89

42

1619

2123

26 9976

7778

8182

7980

29

46 64

39 4748

30

6566

67

53339

846970

71

72

59

57

7374

40

1320

2227

1817

2524

75

stew

mac

.com

4

3

©20

19 S

tew

Mac

S

TE

P 1

21

Sold

er t

ub

e so

cket

V5

Wra

p th

e ju

mpe

r fro

m h

ole

67 to

pin

6 o

f th

e V5

tube

soc

ket .

Wra

p th

e ju

mpe

r fro

m e

yele

t 83

to p

in 1

of

the

V5 tu

be s

ocke

t .

Mak

e su

re th

e ju

mpe

r com

ing

from

hol

e 69

has

con

tinui

ty to

eye

let 5

4 . W

rap

this

ju

mpe

r to

pin

7 of

the

V5 tu

be s

ocke

t .

Wra

p th

e ju

mpe

r fro

m e

yele

t 81

to p

in 8

of

the

V5 tu

be s

ocke

t .

Test

the

two

jum

pers

com

ing

from

hol

e 84

to id

entif

y th

e on

e w

ith c

ontin

uity

to

eyel

et 3

4 . W

rap

this

jum

per

to p

in 2

of

tube

soc

ket V

5 .

Wra

p th

e ju

mpe

r fro

m e

yele

t 85

to p

in 3

of

tube

soc

ket V

5 .

Sold

er th

e co

nnec

tions

to th

is so

cket

(six

w

ires)

and

trim

the

exce

ss w

ire e

nds .

S

TE

P 1

22

Sold

er t

ub

e so

cket

V4

Wra

p th

e ju

mpe

r fro

m e

yele

t 87

to p

in 6

of

the

V4 tu

be s

ocke

t .

Wra

p th

e ju

mpe

r fro

m e

yele

t 89

to p

in 1

of

the

V4 tu

be s

ocke

t .

Wra

p th

e ju

mpe

r fro

m h

ole

70 to

pin

7 o

f th

e V4

tube

soc

ket .

Wra

p th

e ju

mpe

r fr

om e

yele

t 86

to

pin

8 of

the

V4 tu

be s

ocke

t with

the

jum

per

alre

ady

in p

lace

.

Sold

er th

e co

nnec

tions

to th

is so

cket

(six

w

ires)

and

trim

the

exce

ss w

ire e

nds .

S

TE

P 1

23

Sold

er t

ub

e so

cket

V3

Wra

p th

e ju

mpe

r fr

om h

ole

72 t

o pi

n 7

of t

he V

3 tu

be s

ocke

t w

ith t

he ju

mpe

r al

read

y in

pla

ce .

Wra

p th

e ju

mpe

r fr

om e

yele

t 90

to

pin

8 of

the

V3 tu

be s

ocke

t with

the

jum

per

alre

ady

in p

lace

.

Sold

er th

e co

nnec

tions

to th

is so

cket

(six

w

ires)

and

trim

the

exce

ss w

ire e

nds .

S

TE

P 1

24

Sold

er t

ub

e so

cket

V2

Wra

p th

e ju

mpe

r fro

m e

yele

t 92

to p

in 6

of

the

V2 tu

be s

ocke

t .

Wra

p th

e ju

mpe

r fro

m e

yele

t 93

to p

in 1

of

the

V2 tu

be s

ocke

t .

Wra

p th

e un

mar

ked

jum

per f

rom

hol

e 73

to

pin

7 o

f the

V2

tube

soc

ket .

Wra

p th

e m

arke

d ju

mpe

r fro

m h

ole

73 to

pi

n 2

of th

e V2

tube

soc

ket .

Wra

p th

e ju

mpe

r fr

om e

yele

t 91

to

pin

8 of

the

V2 tu

be s

ocke

t with

the

jum

per

alre

ady

in p

lace

.

Wra

p th

e ju

mpe

r fro

m e

yele

t 95

to p

in 3

of

the

V2 tu

be s

ocke

t .

Sold

er th

e co

nnec

tions

to th

is so

cket

(six

w

ires)

and

trim

the

exce

ss w

ire e

nds .

S

TE

P 1

25

Sold

er t

ub

e so

cket

V1

Wra

p th

e ju

mpe

r fro

m e

yele

t 97

to p

in 6

of

the

V1 tu

be s

ocke

t .

Wra

p th

e ju

mpe

r fro

m e

yele

t 98

to p

in 1

of

the

V1 tu

be s

ocke

t .

Wra

p th

e un

mar

ked

jum

per f

rom

hol

e 74

to

pin

7 o

f the

V1

tube

soc

ket .

Wra

p th

e m

arke

d ju

mpe

r fro

m h

ole

74 to

pi

n 2

of th

e V1

tube

soc

ket .

Wra

p th

e ju

mpe

r fro

m e

yele

t 96

to p

in 3

of

the

V1 tu

be s

ocke

t .

Sold

er th

e co

nnec

tions

to th

is so

cket

(six

w

ires)

and

trim

the

exce

ss w

ire e

nds .

S

TE

P 1

26

Sold

er fo

ur

jum

per

s to

co

mp

on

ents

on

th

e b

ack

pan

elTh

e la

st u

nsol

dere

d ju

mpe

r com

ing

from

ho

le 8

4 sh

ould

hav

e co

ntin

uity

to e

yele

t 11

. Sol

der t

his

jum

per t

o th

e m

iddl

e lu

g of

the

vibr

ato

peda

l RCA

jack

.

Sold

er t

he ju

mpe

r fr

om h

ole

66 t

o th

e rig

ht lu

g (ti

p co

nnec

tion)

of t

he e

xten

sion

sp

eake

r ja

ck a

long

with

the

jum

per

in

plac

e .

Sold

er th

e ot

her j

umpe

r fro

m h

ole

28 to

th

e le

ft lu

g of

the

stan

dby

switc

h .

Sold

er t

he ju

mpe

r fr

om h

ole

75 t

o th

e rig

ht lu

g of

the

stan

dby

switc

h .

S

TE

P 1

27

Sold

er t

he

no

rmal

ch

ann

el in

pu

t ja

cks

Slid

e 1"

of

1/8"

hea

t-sh

rink

tubi

ng o

ver

the

mar

ked

jum

per c

omin

g fr

om th

roug

h ho

le 2

7 . S

olde

r thi

s jum

per t

o th

e tw

iste

d pa

ir of

68k

resi

stor

lead

s com

ing

from

the

norm

al c

hann

el in

put

jack

s an

d ap

ply

heat

to

the

heat

-shr

ink

tubi

ng t

o se

al it

to

the

sold

er jo

int .

Sold

er th

e gr

een

jum

per f

rom

eye

let 2

1 to

the

left

lug

(shi

eld

conn

ectio

n) o

f the

in

put 2

jack

.

Sold

er a

ny u

nsol

dere

d re

sist

or le

ads i

nto

plac

e on

the

inpu

t jac

ks n

ow .

Trim

the

exce

ss w

ires .

stew

mac

.com

4

4

©20

19 S

tew

Mac

NO

RMA

LV

OLU

ME

TREB

LEB

ASS

VO

LUM

ETR

EBLE

BA

SSRE

VER

BPI

LOT

SPEE

DIN

TEN

SITY

VIB

RAT

O

21

21

REV

ERB

INPU

TRE

VER

B

OU

TPU

TRE

VER

B

PED

AL

VIB

RAT

OPE

DA

LEX

T. S

PKR

SPEA

KER

STA

ND

BYPO

WER

FUSE

GRO

UN

D

V1

12A

X7

V2

12A

X7

V3

12A

T7V

412

AX

7V

512

AX

7V

612

AT7

V7

6V6

V8

6V6

V9

5AR4A

BC

D

FE

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

4 3

21

87

65

4 3

21

87

65

4 3

21

87

65

1MA

1MA

250KA

250KA

100KL

250KA

250KL

382812

34

56

78

5152

10 34 54 68 8385

8687

9091

9294

9796

95

584349

503231

93614435 60

986362

45

3611

37

5541

1214

15

8856

89

42

1619

2123

26 9976

7778

8182

7980

29

46 64

39 4748

30

6566

67

53339

846970

71

72

59

57

7374

40

1320

2227

1817

2524

75

stew

mac

.com

4

5

©20

19 S

tew

Mac

S

TE

P 1

28

Sold

er n

orm

al c

han

nel

vo

lum

e p

ot

Sold

er t

he u

nmar

ked

jum

per

com

ing

thro

ugh

hole

27

to th

e m

iddl

e lu

g of

the

volu

me

pot .

Cut

a 1”

gre

en ju

mpe

r an

d re

mov

e th

e in

sula

tion .

Ben

d th

is ju

mpe

r in

a “J

” sha

pe

and

run

it fr

om th

e le

ft lu

g of

the

volu

me

pot t

o th

e ba

ck o

f the

vol

ume

pot .

Sold

er

it in

bot

h pl

aces

.

S

TE

P 1

29

Sold

er n

orm

al c

han

nel

tre

ble

po

tFi

nd th

e ju

mpe

r com

ing

thro

ugh

hole

25

that

has

con

tinui

ty t

o ey

elet

45 .

Sol

der

this

jum

per t

o th

e rig

ht lu

g of

the

norm

al

chan

nel t

rebl

e po

t .

Sold

er t

he j

ump

ers

in t

he c

ente

r an

d le

ft lu

gs o

f the

treb

le p

ot if

you

hav

e no

t do

ne s

o .

S

TE

P 1

30

Sold

er n

orm

al c

han

nel

bas

s p

ot

Twis

t tog

ethe

r the

two

jum

pers

com

ing

from

hol

e 24

.

Find

the

jum

per c

omin

g th

roug

h ho

le 2

4 th

at h

as c

ontin

uity

to

eyel

et 2

6 . S

olde

r th

is j

ump

er t

o th

e m

iddl

e lu

g of

the

no

rmal

cha

nnel

bas

s po

t alo

ng w

ith th

e ju

mpe

r alre

ady

in p

lace

.

Find

the

jum

per c

omin

g th

roug

h ho

le 2

4 th

at h

as c

ontin

uity

to

eyel

et 3

7 . S

olde

r th

is ju

mpe

r to

the

left

lug

of th

e no

rmal

ch

anne

l bas

s po

t alo

ng w

ith th

e re

sist

or

lead

alre

ady

in p

lace

.

S

TE

P 1

31

Sold

er v

ibra

to c

han

nel

inp

ut

jack

sSl

ide

1" o

f 1/

8" h

eat-

shrin

k tu

bing

ove

r th

e m

arke

d ju

mpe

r com

ing

from

thro

ugh

hole

20 .

Sol

der t

his j

umpe

r to

the

twis

ted

pair

of 6

8K re

sist

or le

ads c

omin

g fr

om th

e vi

brat

o ch

anne

l inp

ut ja

cks

and

appl

y he

at t

o th

e he

at-s

hrin

k tu

bing

to

seal

it

to th

e so

lder

join

t .

Sold

er th

e gr

een

jum

per f

rom

eye

let 1

6 to

the

left

lug

(shi

eld

conn

ectio

n) o

f the

in

put 2

jack

.

Sold

er a

ny u

nsol

dere

d re

sist

or le

ads i

nto

plac

e on

the

inpu

t jac

ks n

ow .

Trim

the

exce

ss w

ires .

S

TE

P 1

32

Sold

er v

ibra

to c

han

nel

vo

lum

e p

ot

Sold

er t

he u

nmar

ked

jum

per

com

ing

thro

ugh

hole

20

to th

e m

iddl

e lu

g of

the

vibr

ato

chan

nel v

olum

e po

t al

ong

with

th

e ca

paci

tor l

ead

alre

ady

in p

lace

.

Cut

a 1”

gre

en ju

mpe

r an

d re

mov

e th

e in

sula

tion .

Ben

d th

is ju

mpe

r in

a “J

” sha

pe

and

run

it fr

om th

e le

ft lu

g of

the

volu

me

pot

to t

he b

ack

of t

he v

ibra

to c

hann

el

volu

me

pot .

Sold

er it

in b

oth

plac

es .

Als

o so

lder

the

gree

n ju

mpe

r fro

m e

yele

t 12

to

the

back

of

the

vibr

ato

chan

nel

volu

me

pot .

S

TE

P 1

33

Sold

er v

ibra

to c

han

nel

tre

ble

po

tFi

nd th

e ju

mpe

r com

ing

thro

ugh

hole

18

that

has

con

tinui

ty t

o ey

elet

44 .

Sol

der

this

jum

per t

o th

e rig

ht lu

g of

the

vibr

ato

chan

nel t

rebl

e po

t .

Sold

er th

e ju

mpe

rs in

the

cent

er a

nd le

ft

lugs

of t

he v

ibra

to c

hann

el t

rebl

e po

t if

you

have

not

don

e so

.

S

TE

P 1

34

Sold

er v

ibra

to c

han

nel

bas

s p

ot

Find

the

jum

per c

omin

g th

roug

h ho

le 1

8 th

at h

as c

ontin

uity

to

eyel

et 1

9 . S

olde

r th

is j

ump

er t

o th

e m

iddl

e lu

g of

the

vi

brat

o ch

anne

l bas

s po

t alo

ng w

ith th

e ju

mpe

r alre

ady

in p

lace

.

Find

the

jum

per c

omin

g th

roug

h ho

le 1

7 th

at h

as c

ontin

uity

to

eyel

et 3

6 . S

olde

r th

is ju

mpe

r to

the

left

lug

of th

e vi

brat

o ch

anne

l bas

s po

t alo

ng w

ith th

e re

sist

or

lead

alre

ady

in p

lace

.

Als

o so

lder

the

gree

n ju

mpe

r fro

m e

yele

t 6

to th

e ba

ck o

f the

vib

rato

cha

nnel

bas

s po

t .

S

TE

P 1

35

Sold

er t

he

reve

rb p

ot

Find

the

jum

per c

omin

g th

roug

h ho

le 1

3 th

at h

as c

ontin

uity

to

eyel

et 4

2 . S

olde

r th

is ju

mpe

r to

the

right

lug

of th

e re

verb

po

t .

Find

the

jum

per c

omin

g th

roug

h ho

le 1

3 th

at h

as c

ontin

uity

to

eyel

et 1

4 . S

olde

r th

is j

ump

er t

o th

e m

iddl

e lu

g of

the

re

verb

pot

.

Cut

a 1”

gre

en ju

mpe

r an

d re

mov

e th

e in

sula

tion .

Ben

d th

is ju

mpe

r in

a “J

” sha

pe

and

run

it fr

om th

e le

ft lu

g of

the

reve

rb

pot t

o th

e ba

ck o

f the

reve

rb p

ot . S

olde

r it

in b

oth

plac

es .

stew

mac

.com

4

6

©20

19 S

tew

Mac

NO

RMA

LV

OLU

ME

TREB

LEB

ASS

VO

LUM

ETR

EBLE

BA

SSRE

VER

BPI

LOT

SPEE

DIN

TEN

SITY

VIB

RAT

O

21

21

REV

ERB

INPU

TRE

VER

B

OU

TPU

TRE

VER

B

PED

AL

VIB

RAT

OPE

DA

LEX

T. S

PKR

SPEA

KER

STA

ND

BYPO

WER

FUSE

GRO

UN

D

V1

12A

X7

V2

12A

X7

V3

12A

T7V

412

AX

7V

512

AX

7V

612

AT7

V7

6V6

V8

6V6

V9

5AR4A

BC

D

FE

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

4 3

21

87

65

4 3

21

87

65

4 3

21

87

65

3MRA

50KRA

382812

34

56

78

5152

10 34 54 68 8385

8687

9091

9294

9796

95

584349

503231

93614435 60

986362

45

3611

37

5541

1214

15

8856

89

42

1619

2123

26 9976

7778

8182

7980

29

46 64

39 4748

30

6566

67

53339

846970

71

72

59

57

7374

40

1320

2227

1817

2524

75

stew

mac

.com

4

7

©20

19 S

tew

Mac

S

TE

P 1

36

Sold

er t

he

spee

d p

ot

Find

the

jum

per c

omin

g th

roug

h ho

le 3

3 th

at h

as c

ontin

uity

to

eyel

et 6

8 . S

olde

r th

is ju

mpe

r to

the

right

lug

of th

e sp

eed

pot .

Sold

er th

e 6 .

8K re

sist

or le

ad in

the

cent

er

and

left

lugs

of t

he sp

eed

pot i

f you

hav

e no

t don

e so

.

S

TE

P 1

37

Sold

er t

he

inte

nsi

ty p

ot

One

of t

he w

ires

com

ing

thro

ugh

hole

9

will

hav

e co

ntin

uity

to e

yele

t 32

and

one

of t

hem

will

hav

e co

ntin

uity

to

eyel

et

8 . F

ind

thes

e tw

o w

ires

and

twis

t th

em

toge

ther

.

Find

the

jum

per c

omin

g th

roug

h ho

le 9

th

at h

as c

ontin

uity

to

eyel

et 3

2 . S

olde

r th

is ju

mpe

r to

the

right

lug

of th

e in

tens

ity

pot .

Find

the

jum

per c

omin

g th

roug

h ho

le 9

th

at h

as co

ntin

uity

to e

yele

t 8 . S

olde

r thi

s ju

mpe

r to

the

mid

dle

lug

of th

e in

tens

ity

pot .

Cut

a 1”

gre

en ju

mpe

r an

d re

mov

e th

e in

sula

tion .

Ben

d th

is ju

mpe

r in

a “J

” sha

pe

and

run

it fr

om th

e le

ft lu

g of

the

inte

nsity

po

t to

the

back

of t

he in

tens

ity p

ot . S

olde

r it

in b

oth

plac

es .

S

TE

P 1

38

Sold

er t

wo

tra

nsf

orm

er le

ads

Fin

d t

he

red

lea

d f

rom

th

e o

utp

ut

tran

sfo

rmer

co

min

g t

hro

ug

h t

he

gro

mm

eted

ho

le b

etw

een

th

e 6V

6 tu

bes .

Trim

it t

o an

app

ropr

iate

leng

th

and

sold

er it

to e

yele

t 46 .

Find

the

red

lead

from

the

reve

rb d

river

co

min

g th

roug

h th

e gr

omm

eted

hol

e be

twee

n tu

be so

cket

V3

and

tube

sock

et

V4 . T

rim it

to a

n ap

prop

riate

leng

th a

nd

sold

er it

to e

yele

t 88 .

S

TE

P 1

39

Sold

er b

ias

bo

ard

jum

per

sSo

lder

the

gree

n ju

mpe

r fro

m e

yele

t E o

f th

e bi

as b

oard

to

the

near

by t

hree

-lug

grou

ndin

g st

rip .

Sold

er th

e re

d/bl

ue le

ad fr

om th

e po

wer

tr

ansf

orm

er to

eye

let A

of t

he b

ias b

oard

.

Sold

er th

e ju

mpe

r fro

m h

ole

D to

the

right

lu

g of

the

bias

pot

.

Find

the

jum

per c

omin

g th

roug

h ho

le 9

th

at h

as c

ontin

uity

to

eyel

et 1

0 . S

olde

r th

is ju

mpe

r to

eyel

et C

of t

he b

ias b

oard

.

S

TE

P 14

0

Sold

er b

ias

po

t ju

mp

ers

Sold

er th

e ju

mpe

r fro

m h

ole

D to

the

right

lu

g of

the

bias

pot

.

Sold

er t

he ju

mpe

r fr

om h

ole

30 t

o th

e m

iddl

e lu

g of

the

bias

pot

.

S

TE

P 14

1

Ad

d t

wo

res

isto

rsTw

ist

the

lead

s of

tw

o 10

0Ω r

esis

tors

to

geth

er a

nd a

pply

sol

der t

o ke

ep th

em

join

ed . W

rap

the

two

resis

tors

’ oth

er le

ads

onto

the

pilo

t la

mp

lugs

alo

ng w

ith th

e gr

een

pow

er t

rans

form

er le

ads .

Do

not

sold

er th

ese

yet .

Sold

er t

he t

wis

ted

lead

s to

eye

let

E on

th

e bi

as b

oard

.

S

TE

P 14

2

Sold

er t

wo

filt

er c

ho

ke le

ads

Find

the

two

blac

k le

ads c

omin

g th

roug

h th

e g

rom

met

ed h

ole

bet

wee

n t

ube

sock

ets

V7 a

nd V

8 .

Sold

er o

ne o

f the

se le

ads

to e

yele

t 29 .

Sold

er th

e ot

her l

ead

to e

yele

t 64 .

S

TE

P 14

3

Inst

all t

wo

gre

en ju

mp

ers

Cu

t tw

o 15

-1/2

” g

reen

jum

per

s an

d tw

ist t

hem

toge

ther

, lea

ving

one

inch

of

untw

iste

d w

ire o

n ea

ch s

ide .

Wra

p th

e tw

o w

ires

from

one

sid

e of

thi

s tw

iste

d pa

ir th

roug

h th

e tw

o lu

gs o

f th

e pi

lot

lam

p as

sem

bly .

Sol

der

thes

e le

ads

into

pl

ace

with

the

two

100Ω

resi

stor

s and

the

gree

n po

wer

tran

sfor

mer

lead

s .

Rout

e th

ese

twis

ted

jum

pers

aro

und

the

edge

of

the

chas

sis

to r

each

soc

ket

V8,

but l

eave

room

for t

he c

hass

is m

ount

ing

scre

ws

to m

ake

it th

roug

h th

eir

hole

s .

Thes

e ar

e th

e tw

o ho

les v

ery

clos

e to

the

left

wal

l of t

he in

side

of t

he c

hass

is .

stew

mac

.com

4

8

©20

19 S

tew

Mac

NO

RMA

LV

OLU

ME

TREB

LEB

ASS

VO

LUM

ETR

EBLE

BA

SSRE

VER

BPI

LOT

SPEE

DIN

TEN

SITY

VIB

RAT

O

21

21

REV

ERB

INPU

TRE

VER

B

OU

TPU

TRE

VER

B

PED

AL

VIB

RAT

OPE

DA

LEX

T. S

PKR

SPEA

KER

STA

ND

BYPO

WER

FUSE

GRO

UN

D

V1

12A

X7

V2

12A

X7

V3

12A

T7V

412

AX

7V

512

AX

7V

612

AT7

V7

6V6

V8

6V6

V9

5AR4A

BC

D

FE

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

4 3

21

87

65

4 3

21

87

65

6

4321

98 7 5

6

4321

98 7 5

6

4321

98 7 5

4 3

21

87

65

382812

34

56

78

5152

10 34 54 68 8385

8687

9091

9294

9796

95

584349

503231

93614435 60

986362

45

3611

37

5541

1214

15

8856

89

42

1619

2123

26 9976

7778

8182

7980

29

46 64

39 4748

30

6566

67

53339

846970

71

72

59

57

7374

40

1320

2227

1817

2524

75

Step

147

: Tw

ist p

ins

4+5

toge

ther

on th

ese

sock

ets.

stew

mac

.com

4

9

©20

19 S

tew

Mac

Inst

all t

he

hea

ter

wir

esRe

view

thes

e st

eps

very

car

eful

ly b

efor

e yo

u st

art i

nsta

lling

the

heat

er w

ires

that

po

wer

the

heat

ing

filam

ents

in th

e tu

bes .

The

twis

ted

gree

n w

ires

from

the

pow

er

tran

sfor

mer

car

ry A

C vo

ltage

to th

e he

at-

ing

filam

ents

in th

e tu

bes .

It’s

impo

rtan

t to

twis

t the

se w

ires t

ight

ly to

geth

er . T

his

isn’

t fo

r lo

oks;

tw

istin

g th

e w

ires

has

a hu

m-c

ance

lling

fun

ctio

n th

at r

educ

es

nois

e in

the

amp .

S

TE

P 14

4

Co

nn

ect

to t

ub

e so

cket

V8

Cut

two

6" h

eate

r w

ires,

one

whi

te a

nd

one

bla

ck . T

wis

t th

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STEP 154

Install the fuseInsert the 1-amp fuse into the fuse socket and make sure the socket cap is secure . Never use a fuse rated above 1 amp in this amplifier .

STEP 155

Install the capacitor panUse the self-tapping screws to mount the capacitor pan on the chassis, covering the filter cap board .

Installing parts and preparing for testing

STOP!

DON’T INSTALL THE TUBES YET! DON’T PLUG THE AMP IN YET!

The next page is going to keep you out of trouble!

STEP 158

Set the chassis on a chassis stand or on blocks for testingSet your chassis up for final testing . Chassis stands are extremely useful for this . If you do not have a chassis stand a couple of blocks of wood can work just fine .

STEP 156

Install the pilot lampInsert the pilot lamp bulb into its socket from the front of the chassis and twist until it locks back in place . Screw the red jewel lens over the socket .

STEP 157

Install the control knobsTurn the shaft of each pot to “zero” and install the knob so that the indicator line points to number 1 .


STEP 161

Test the dangerous DC voltageThe dangerously high DC voltage that passes through the rectifier tube and the filter caps is referred to as “B+” . The next step is to test this B+ voltage .

With the amp still unplugged and turned off, install the 5AR4 rectifier tube while spreading the tension clip .

Plug the power cord back in and turn the power switch to ON . The pilot lamp should light, along with the filament inside the 5AR4 rectifier tube .

Again, spend a few minutes watching for smoke or smells before flipping the standby switch to ON .

For safety, use only one hand to probe the amp during DC tests. Keep your other hand behind your back when probing a component, so you can’t be a path between B+ voltage and ground—a mistake that would send a dangerous charge through your heart .

Set your multimeter to 600V DC and connect the negative lead to ground . Once the negative lead is secured to ground, flip the standby switch to ON . Measure the DC voltage at eyelet 46 for your B+ voltage . This should be roughly 490V DC .

Turn the power and standby switches to OFF and unplug the amp .

Any multimeter will work fine for the two types of tests we’re about to do: checking continuity and reading voltages . The instructions that came with your meter will be helpful .

Continuity testing is simply making sure current f lows between two points successfully . Touch the meter's red lead to one end of the section being tested, and the black lead to the other end . If the continuity is good, your meter will beep or register this on the display .

Voltage testing is where you need to be careful . Some steps require the amp to be plugged in and turned on . This becomes dangerous if you’re not cautious . Respect the voltages and follow the directions, and these tests are safe and easy .

STEP 159

Perform a safe power-upAt this point, there should be no tubes installed, and the speaker should be disconnected .

Before plugging the amp in, turn the power switch to ON . Switching the amp on before the first power-up protects you from shock if a mistake in your wiring has created a short to the chassis . If this short exists, an indication would be that the pilot light will not turn on, since the AC current is going directly to ground .

Plug the power cord in . The pilot lamp should light .

For a few minutes, watch for smoke or unusual smells . If anything seems unusual, disconnect the power immediately and carefully review all your connections .

STEP 160

Test the standard AC voltageSet your multimeter to 20V AC . Check the heater voltage across pin 9 and pins 4+5 on the V1 12AX7 socket . This should read between 5-7V AC . If this reading is drastically different, disconnect power and check your connections .

If the amp seems normal, unplug the power cord and turn the power switch OFF .

Testing and troubleshooting

V1

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0VALWAYS discharge the filter cap

before working on the circuit. See how

to use a snuffer stick on page 6.

And seriously, keep one hand behind

your back!


STEP 162

Test the preamp tubesWith the amp unplugged use the snuffer stick to discharge the capaci-tors, then install the six preamp tubes .

After these tubes are installed, plug the amp back in and flip the power switch ON . The pilot lamp should light up . Let the amp warm up for a few minutes and then flip the standby switch to ON . Again, if you get smoke or smells, unplug immediately .

Connect your multimeter’s negative lead to ground .

Set the multimeter to 5V DC and check eyelet 96, which should read around 1 .3V .

Set the multimeter to 200V DC and check eyelet 98 . It should read around 200V .

Set the multimeter to 100V DC and test pin 5 of the V7 and V8 sockets . These readings should be nearly identical .

Use a small flathead screwdriver to turn the center of the bias pot all the way counter-clockwise . This will set the bias for the lowest negative DC voltage . Doing this provides a safe voltage for the power tubes while you set the initial bias .

If all of these voltages come within approximately 10% of their expected values, turn the power switch OFF . Always turn the power switch off before turning the standby switch off . This will drain the filter capacitors as the amp cools down . After a moment, flip the standby switch OFF as well .

If the reading at eyelet 98 shows no voltage or low voltage, follow this test: unplug the amp, drain the filter caps with the snuffer stick, set your meter to read continuity, and make sure you have properly installed the back-of-board jumper from eyelet 35 to eyelet 62 .

STEP 163

Test the 6V6 power tubesWith the amp unplugged, install the 6V6 power tubes, turning them so their indexing keys fit correctly in the socket . Turn all of the front panel con-trols completely counter-clockwise, so the indicator line is pointing to "1" .

Plug the speaker in and perform these next tests with the speaker turned away from you . If the amp starts to oscillate and squeal, this will help protect your ears .

Plug the amp in and flip the power switch ON . Give the tubes 30 seconds to warm up and then flip the standby switch to ON as well .

After a few moments you should hear a low hum . If the hum becomes very loud, disconnect the power immedi-ately and review your connections .

Set your multimeter to read 500V DC and test for voltage on pin 3 of both socket V7 and socket V8 . This is the plate voltage reading, and it will be around 415V . Write this number in Box 2 of the calculation in Step 167 . It’ll be needed if you use a bias meter to set your bias .

Set your multimeter to read 50V DC and test for voltage at eyelet 39 . Adjust the bias pot until this voltage reads -35V .

If all of these voltages come within approximately 10% of their expected values, turn the power switch OFF . After a few moments turn the stand-by switch OFF as well, and unplug the amp .

Tube bias affects your sound“Bias” refers to the current of elec-trons flowing from the cathode to the plate inside your power tubes when the tubes are idle . The bias setting determines this flow and is increased or decreased by the screwdriver-ad-justable bias pot .

Adjusting the bias affects your sound: a higher setting gives you punchier cleans and grittier distortion, but your tubes will wear out faster . With a low setting, your tubes last longer but the sound is more sterile . A good bias setting falls between these extremes .

Testing and troubleshooting


STEP 164

Old method of setting the bias: doing it by earIf you have a bias meter, skip this step and go on to Step 165 .

The old-school way of adjusting the bias is by ear: after setting the bias voltage to a recommended starting point, you make tiny adjustments to the bias pot while listening for the sound you want . This inexact method can shorten the life of your power tubes .

You roughed-in the bias setting in the previous step by setting the bias voltage at -35V .

Danger: set your guitar aside before you adjust the bias pot. Do not touch any amp circuitry while holding your guitar . Doing so would create an electricution hazard!

Use a screwdriver to make a tiny adjustment to the bias pot . Turn clockwise to increase the current and counter-clockwise to decrease it . Then set the screwdriver aside and play to hear to the result .

Watch out for red-platingYou especially want to avoid too much current turning the gray plates to glowing red . If your tubes start red plating, shut the amp down and let it cool before setting the bias to a lower level .

STEP 165

Improved method of setting the bias: using a bias meterThe more accurate way to set the bias is by using a bias meter, such as the VHT Bias Tester (StewMac #1580) .

This method starts with a simple cal-culation to find your bias setting, then you adjust the bias pot until your bias meter displays that reading .

The calculation uses two numbers, the tube’s maximum plate dissipation and its plate voltage .

Plate dissipation. Every power tube has a specified plate dissipation—the maximum wattage the tube can handle . For the 6V6 power tubes in this amp, that maximum is 14 watts . Exceeding the 14-watt limit will dam-age the tube, and operating at the full 14 watts will shorten its life . Our goal is to operate the tube at 60% of the 14-watt limit, or 8 .4 watts . We've entered this number for you in Box 1 of the calculation .

Plate voltage. You already have the plate voltage for these tubes: it’s the the number you found in Step 163 and wrote in Box 2 below .

Divide Box 1 by Box 2. The result is your recommended bias setting for use in the next step . Our example cal-culation gives a bias recommendation of .020 Amps . Since bias is typically measured in milliamps, this measure-ment is written as 20mA .

Calculate your bias current setting

Example:

Your plate voltage from Step 16560% of max. plate dissapation

÷Your bias current setting

=8.4

BOX 2BOX 1

8.4 ÷ =

With the amp unplugged allow the power tubes to cool . Once the power tubes have cooled, remove them from their sockets .

Plug the tubes in to the bias probe sockets, which are like tube sockets . Plug the probe sockets with tubes into the power tube sockets .

Plug the amp back in and flip the power switch ON . Give the tubes 30-60 seconds to warm up, then flip the standby switch ON .

Watch the bias meter as the power tubes heat up . Both needles should rise at an equal rate and settle at the same time .

Adjust your bias pot until the bias meter displays the reading you calcu-lated (20mA in our example) . Let the amp idle for a few minutes to make sure that the bias doesn’t drift .

When you see a constant readout of your bias setting, turn the power switch OFF .

After a few moments flip the standby switch OFF and unplug the amp from the wall .

Once the tubes are cool, remove them and the bias probes from the amp and plug the tubes back in to the amp's tube sockets without the probes attached .


After playing for a few minutes and testing all inputs, if everything seems to be operating normally, go ahead and turn the amp off . Install the chassis into the cabinet, install the power cord clamp in the side wall of the cabinet, install the preamp tube shields, and install the back panels .

STEP 166

Test the reverb and tremoloConnect the two shielded cables you assembled in Step 7 to the reverb in and out jacks on the back of the chassis . Connect the chassis out cable to the reverb tank’s in jack . Connect the chassis’s in cable to the out jack on the reverb tank . Also connect the footswitch cables to the reverb and vibrato jacks .

Plug the amp back in and flip the power switch ON . Allow the tubes to warm up for 30 seconds, then flip the standby switch ON .

Plug your guitar into the normal channel and play at low volume . If the amp behaves as it should, test the tone controls and keep increasing the volume . The 66D should start to break up nicely as you increase the volume .

Now test the vibrato channel effects . If the reverb isn’t working, try switch-ing the cables in the reverb in and out jacks . If that doesn’t remedy the issue, check your reverb cables again for a short .

If there are any strange oscillations, squeals, or the amp seems at all unsta-ble, use a wooden chopstick to begin probing for loose connections: n from the input jacks to the eyelet boardn from the tube sockets to the eyelet boardn from the tube sockets to the front panel controls . It usually takes just a minor wiring ad-justment, perhaps resoldering a loose joint, to correct this sort of distortion .

Final assembly

STEP 167

Install the chassisDischarge the capacitors so you can safely handle the amplifier . Remove all the cables from their jacks .

Slide the chassis in from the back until its front edge rests on the speaker baffle . Align the chassis straps with the holes in the top of the cabinet . Insert the mounting screws through the straps and down through the chassis . Tighten the locknuts .

Install the preamp tube shields . Fas- ten the power cord to the cable clamp on the side of the cabinet and install the back panels .

Slide the reverb tank into its bag and lay it on the floor of the cabinet . The RCA connections inside the bag should be facing front, toward the speaker baffle .

Plug in the speaker, footswitch, and reverb tank .

It's finally time to let it rip!

GO!GO!


Tube lifeThe life span of the power tubes is affected by how hard you drive the amp . If you are overdriving the amp for hours every day, expect the power tubes to have a shorter life span .

We encourage you to experiment with different tube brands and find the brand that is most favorable to your ears and your wallet .

For questions and support, StewMac is here to help!For more than fifty years, StewMac has supplied instrument builders and repair shops . Our customer service team really knows how to help if you run into questions .

Call 800-848-2273 from 9AM–6PM Eastern time, Monday–Friday . Email: service@stewmac .com

Thanks for choosing this StewMac ICON KIT, and welcome to the world of amp building!

Tips for using the 66D

Enjoy your amp!For many players, this is a “desert island” amp: the one to choose if you could only have one amplifier .

It has very little hum for a vintage circuit, the reverb is cavernous, and the distortion is just right . Also, the tremolo doesn’t make the unwanted ticking noise you find with some vin-tage tremolos . (Speaking of tremolo, Leo mistakenly named this effect “vi-brato,” but let’s forgive him for that .) .

Why is this amp so sweet, and how do you dial it in? The AB763 tone stack has a distinct mid scoop: the bass and treble controls boost their ranges while leaving the mids unaffected . With bass and treble set to minimum, the tone stack bleeds off about 25dB from the signal . For this reason, try setting the bass and treble at about 6 . If you’re using single-coils, maybe bump the bass up a bit more, and give humbuckers a little more treble .

The normal channel doesn’t have reverb and tremolo . This unaffected channel is helpful if you have a reverb pedal on your board and don't want to send your signal through a reverb tank . However, most players seem to prefer the vibrato channel .

With the bass and treble at about 6, try the reverb control between 4 and 5 .

You can vary the tremolo speed and intensity settings quite a lot depend-ing on the song, but the tremolo can become overwhelming when the intensity goes past 6 .

I usually play with the volume control on my guitar at 10, and the 66D sits right on the edge of distortion with the volume around 5 .5-6 . Increasing the volume past that point doesn't make the amp louder, but the tubes start to saturate and the tone goes into full-on gorgeous, harmonic distortion .

There’s no right or wrong way to play this amp, and it’s almost impossible to pull a sour tone from it!

Matt Clouston, StewMac


OutputGain

Negative feedback

Processing

Power

Mic level

Speaker levelLine level Line level

You don’t need to read a schematic to build this kit . But it’s fun to see how the circuit works, and to see the different subcircuits that interact to shape your sound .

Working with the tiny signal from the guitar, the amp creates the power needed to drive the speaker . The signal is affected by the gain, processing, output and power stages as it passes through the circuit .

The gain circuit increases the signal strength to line level (about 1 volt), by passing it through preamp tubes .

Inside the tube, electrons flow from a heated cathode to be received by the anode plate . Between these is a grid receiving the tiny voltage from the guitar . The guitar’s varying musical signal controls the flow of electrons to the plate .

V1 handles the first gain stages of the normal channel, and V2 handles the first gain stages of the vibrato chan-nel . The vibrato channel has an extra gain stage in the second half of V4 to make up for signal lost through the reverb and vibrato circuits .

The negative feedback loop flattens and extends the amp’s frequency re-sponse, reducing distortion generat-ed in the output stage . This makes the amp’s sound cleaner and more hi-fi .

Some players disable this loop com-pletely or add a potentiometer in place of the resistor to create a “grit control .” We don’t recommend this, because it places stress on the output transformer .

The processing stage shapes the tone . The AB763 is notorious for its mid-scooping tone stack .

Both the normal channel and the vibrato channel have processing con-trols through their respective treble and bass controls, and the vibrato channel has additional processing through the reverb and vibrato cir-cuits .

V3 handles the reverb send and the first half of V4 handles the reverb re-covery . V5 handles the vibrato circuit .

Both channels are then sent to the phase inverter which uses all of V6 . The phase inverter then sends the signal to the output section .

The power supply stage provides power to the other circuit stages, as well as the tube heaters and pilot light .

This circuit receives the AC power from your wall and passes it through the power transformer to create higher voltage . The electricity then goes to the rectifier, which converts it to a pulsing DC current .

This then passes through the filter choke and the filter cap board . The filter cap board contains five capacitors that filter out the pulsing to create a smooth current . As each cap smoothes a bit more, the current is also passing through resistors that lower the voltage .

As the signal from the guitar becomes more amplified, the ripple of DC current becomes less evident and the fully filtered current is sent to the most sensitive part of the amplifier, the first pre-amp tube in the Gain stage .

The output stage increases the line level signal to speaker level, which is typically 8 volts or greater .

Two 6V6 tubes drive the output trans-former . They receive the split signal, 180 degrees out of phase, amplify those signals, and send them to the output transformer to be recombined into one signal . This transformer adjusts the impedance to 8 ohms to drive the amp’s 8Ω speaker .

This amp has an adjustable fixed bias, which means you need to check the bias and possibly make adjustments when you change power tubes .

cathode

plate

grid

We’ve color-coded these stages on our schematic, to show how the parts work together . Symbols for components are in the key at the bottom of the frame .

On the wiring diagram we build step-by-step in these pages, the parts are easier to recognize . But studying these color-coded stages will help you understand where each component fits into the creation of your sound .

Learning more: secrets revealed in the schematic


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It’s your amp. Your tone. You built it!

’57 MINI TWEED 5W AMP KITOne-knob titan of tone.A timeless studio darling whose tiny size hides tremendous punch and versatility .

The 5F1 circuit was meant to be a student amp but wasn’t kid stuff for long; rock’s finest guitarists hijacked it for some of the greatest songs ever recorded . Listen to Eric Clapton (“Layla") or Joe Walsh (“Rocky Mountain Way") while you build this amp!

Our simplest kit; the quickest way to get into amp building .

#10730 5 WATTS / 8" SPEAKER / ORIGINAL 5F1 CIRCUIT

’65 P-REVERB 15W AMP KITSparkling bright, perfect for the surf.Plug your single-coils straight in for that signature clean American tone, or go surfing with onboard effects .

The smallest member of the black-panel family to offer reverb and tremolo, this amp made its name as a jangly pop dream machine . Aficionados treasure its early low-end breakup powered by a pair of 6V6 tubes .

Listen to “Surfin’ USA" and the great sounds of Ryan Adams .

#10734 15 WATTS / 10" SPEAKER / ORIGINAL AA1164 CIRCUIT

’66 D-REVERB 22W AMP KITFamously clean, with enough guts to gig.Perfect for recording as well as performing, the D-Reverb produces stinging clarity that absolutely refuses to get lost in the mix .

One of the most popular designs ever, this amp lives in the happy middle between bright clarity and rich distortion . It excels in the studio and on the stage . While capable of crystal clear tones at good volume, you can push this one into beautifully saturated, play-sensitive distortion .

It’s all here: clarity, distortion, and rectifier tube sag .

#10737 22 WATTS / 12" SPEAKER / ORIGINAL AB763 CIRCUIT

H OU RS : 6

D I F F I C U LTY

H OU RS : 1 2

D I F F I C U LTY

H OU RS : 8

D I F F I C U LTY

H OU RS : 16

D I F F I C U LTY

’59 TWEED 15W AMP KITDirty little devil that shaped guitar history.With mysteriously fat saturated tone, this little monster makes it easy to achieve seismic distortion .

This amp’s 5E3 circuit is an enigma: Why do the controls on the channel you’re NOT using make your tone so great? The answer: Who cares? This is one of the greatest tone monsters ever created! Listen to Neil Young’s Rust Never Sleeps while building this kit .

Our most popular amp kit and a great learning experience .

#10731 15 WATTS / 12" SPEAKER / ORIGINAL 5E3 CIRCUIT

StewMac ICON KITS teach you the world of amp building, then turn you loose with amazing hand-built tone machines!


’62 BRIT-PLEX 45W AMP KITThe original British showstopper.This amp started a revolution . It’s been rocking the world for over 50 years, and we still can’t get enough .

Favored by blues and rock players for exceptional sustain and rich creamy tone, the ’62 Brit-Plex is chock-full of harmonic gain, yet it still stays articulate and even a little crispy . Put this head on a classic 4x10 cab and watch out!

While building, listen to Gary Moore’s “Still Got The Blues ."

#10736 45 WATTS / ORIGINAL BRITISH CIRCUIT

’66 BRIT-74X 18W AMP KITLeave your half-stack at home.Born in London, this little blues blaster earns its living every night, gigging in clubs across the USA .

Launched in 1966, this amp quickly became a low-wattage holy grail . This is a stripped-down blues machine: two channels, one tone knob, no master volume . Buckle up and go where this gritty beast takes you! It comes with a footswitch to kick in the onboard tremolo .

Get the plexi tone without blowing the roof off the joint!

#10732 18 WATTS / 12" SPEAKER / ORIGINAL BRITISH CIRCUIT

’81 BRIT-800 50W AMP KITThis hairy monster lives to shred.The defining British circuit that dominated the ’80s .

This 50W giant created your favorite heavy rock and metal albums . Used by Slayer and Pixies, and recorded on early Metallica albums, this circuit produces that screaming guitar tone that your mother despises . With solid-state rectification there’s no sag, and the distortion created by this circuit is way more about treble than mids or bass .

Listen while building: Smashing Pumpkins’ Siamese Dream .

#10735 50 WATTS / ORIGINAL BRITISH CIRCUIT

’64 REVERB UNIT KITReverb you can’t get from a pedal.This is the unit that put the waves in surf music! Looks like an amp, sounds like a beach party .

This tube-driven reverb tank relies on good ol’ physics for a perfect effect . Your guitar signal travels along two large suspended springs to produce the reverb that launched the iconic surf sound . This isn't a pocket-sized digital simulation; this is the real deal!

Listen to Dick Dale’s “Misirlou" while doing this easy build .

#10733 ORIGINAL 6G15 CIRCUIT

H OU RS : 1 2

D I F F I C U LTY

H OU RS : 1 2

D I F F I C U LTY

H OU RS : 16

D I F F I C U LTY

H OU RS : 8

D I F F I C U LTY

Beginner-tested. Pro quality.StewMac ICON KITS are fun to build, with friendly instructions to guide you and loads of info to add to your knowledge.


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StewMac®

I C O N K I T S



12AX7(ECC83)

12AX7(ECC83)

V5 V4

6V6 12AT7(ECC81)

V7 V6

12AX7(ECC83)

12AX7(ECC83)

V2 V1

12AT7(ECC81)

V3

5AR4(GZ34)

6V6

V9 V8

#10737


StewMac®

I C O N K I T S



12AX7(ECC83)

12AX7(ECC83)

V5 V4

6V6 12AT7(ECC81)

V7 V6

12AX7(ECC83)

12AX7(ECC83)

V2 V1

12AT7(ECC81)

V3

5AR4(GZ34)

6V6

V9 V8

#10737

Cut this label on the dotted line with a razor knife and metal straightedge .Fasten it inside the cabinet using thinned wood glue or contact cement .

The duplicate copy below is included as a backup .



tools + ideas for guitarmakingStewMac

21 N . Shafer St ., Athens, OH 45701800-848-2273 stewmac .com

©2019 StewMac . All rights reserved .#10737 Updated February, 2019

Documents

’66 D-REVERB 22W · Solder Monster #3000 Guitar Tech Screwdriver Set #1606 Wire Stripper #1607 Wire Cutter #0501 Solomon SL-30 Soldering Station #1609 Round Nose Bending Pliers