Sheet #i-2150 Updated 12/17
StewMac
JHS 808
CLASSIC PEDAL KIT
Assembly Instructions
The JHS808 is one of the great stompboxes from JHS, makers of high-end effects pedals. Whenever JHS adds a new
pedal to their line, they retire an existing design. This means
great JHS pedals like the JHS808 have become rare and
sought-after. You can’t buy one, but you can build yourself
one—and it’s fun!
Easy instructions!
Clear pictures show where
each part goes.
Back in the late 1970s, Ibanez introduced the TS-808 Tube
Screamer, possibly the most famous overdrive pedal ever
made. Favored by many discriminating guitarists, including
Stevie Ray Vaughan, Eric Johnson, and Joe Bonamassa. Often
copied or modded, the Tube Screamer circuit has become
the platform for most modern overdrive pedals.
Using an original vintage TS-808 as a starting point, Josh
Scott modded the circuit to include a three-way gain toggle
that switches between the stock circuit, boost, and crunch
for added flexibility. The result is this JHS808.
stewmac.com ©2017 Stewart-MacDonald page 1 of 12
Tools and supplies
Tips for soldering
Required: Soldering iron with fine point tip
Solder
Wire cutter/stripper
1/2" nut driver or socket
10mm nut driver or socket
14mm wrench
#1 Phillips screwdriver
Also helpful: Clear silicone adhesive
Circuit card holder
Magnifying glass or OptiVISOR
StewMac Soldering Aids
Power: This pedal requires a standard 9V DC
center-negative power supply (not
included) and consumes less than 100mA.
There’s no battery option.
The solder joints you’ll make on the
circuit board are very small, and too
much heat can damage the board.
The idea is to make joints quickly,
without scorching the eyelets.
Hold components in place for soldering by threading the
leads through the board and bending them apart on the
reverse side.
Make your solder joints on the reverse side. Insert the tip into
the eyelet and let it heat for 4-5 seconds before touching it
with solder. This heats the contact enough for the solder to
flow nicely without damage. You don’t need much solder,
just enough to fill the eyelet. After soldering, trim away the
excess lead wire.
Give your pedal a custom paint job!
Any paint sold for use on metal will work well on the kit case.
Spray paints like Rustoleum® or Krylon® are a durable finish.
You might want to paint the case before building the kit,
so you won’t need to take the parts back out for painting.
A way to add custom graphics is to print them from your
computer onto waterslide decal paper. If you use decals,
protect them from scratches by spraying clear topcoats
over them.
stewmac.com ©2017 Stewart-MacDonald page 2 of 12
parts: i-2150 808
(1) On-Off-On solder lug toggle
(1) DC power connector (2.1mm)
(1) Footswitch (3PDT, latching)
(1) Metal case with 4 screws
(1) Circuit board
(Not pictured)
(Not pictured)
(1) C7 Capacitor (.047 µF)
(1) LED mounting bezel (5mm)
(2) Mono jacks, 1/4"
(1) D1 Diode (P6KE22A)
(3) D2, D3, D7 Rectifiers
(2) C6, C13 Capacitors (1 µF)
(2) D4, D5 Red LEDs (5mm)
(1) D8 Clear LED (5mm, glows yellow)
(1) U1 Low noise op-amp (4558P 500nA)
(1) U1.2 socket for op-amp
(3) C2, C12, C14 Capacitors (.1 µF)
(1) C5 Capacitor (.027 µF)
(1) C8 Capacitor (51 pF)
(2) C1, 15 Capacitors (10 µF)
10uF
(1) R11 Pot (500 kΩ, linear taper)
(1) R18 Pot (100 kΩ, linear taper)
(1) R14 Pot (5 kΩ, linear taper)
.22J6347NJ
NPO 51J
27nJ63
100uF
(2) C3, C4 Capacitors (100 µF)
(2) C9, C10 Capacitors (.22 µF)
(1) Ribbon cable
(2) Q1, Q2 Transistors (2n3904)
(1) Lead wire (12")
(4) Adhesive foam tape
(3) Control knobs
.1J63
1J63
Parts list
Resistor values are indicated by colored bands, read from left
to right. The first color in the code is usually the one painted
closest to a lead wire. When a gold or silver band is present,
it’s always one of the last colors in the code. A magnifier is
a big help in reading these codes.
Yellow Purple Black Red Brown
Brown Black Black Brown Brown
Red Red Black Yellow Brown
Green Brown Yellow G old
Brown Black Black Red Brown
Yellow Purple Black Brown Brown
Green Brown Black Red Brown
Red Red Black Black Brown
Brown Black Black Black Brown
Yellow Purple Black Gold Brown
(2) R1, R2 Resistors (47 kΩ)
(5) R3, R5, R12, R16, R17 (1 kΩ)
(1) R4 Resistor (2.2 MΩ)
(2) R6, R19 Resistors (510 kΩ)
(5) R7, R8, R13, R20, R22 (10 kΩ)
(1) R9 Resistor (4.7 kΩ)
(1) R10 Resistor (51 kΩ)
(1) R15 Resistor (220 Ω)
(1) R21 Resistor (100 Ω)
(1) R23 Resistor (47 Ω)
10uF
(2) C1, 15 Capacitors (10 µF)
100uF
(2) C3, C4 Capacitors (100 µF)
(3) C2, C12, C14 Capacitors (.1 µF)
27nJ63
.1J63
(2) C9, C10 Capacitors (.22 µF)
.22J6347NJ
(1) C5 Capacitor (.027 µF)
(2) C6, C13 Capacitors (1 µF)
1J63
NPO 51J
(1) C7 Capacitor (.047 µF)
(1) C8 Capacitor (51 pF)
(1) D1 Diode (P6KE22A)
(3) D2, D3, D7 Rectifiers
stewmac.com ©2017 Stewart-MacDonald page 3 of 12
Step 1: Install twenty resistors
JHS Pedals Kit
For Stew Mac
R11
D5
D4
R9
R8
R6
R7
S
C5
T
JHS Pedals Kit
For Stew Mac
R11
D5
D4
R9
R8
R6
R7
S
C5
T
DC Jack
R10
D7
D3
C7
Q1 Q2
D8
DC Jack
R10
D7
D3
C7
Q1 Q2
R23
C4
R12
C8 C12
D2
R13
R14
C10
C6 C13
R15
R23
C4
R12
C8 C12
D2
R13
R14
C10
C6 C13
R15
R5
D1
C2
R1
C3
C1
R2
U1
R4R5 R20
D1
C2
R1
C3
C1
R2
U1
R4
R20
R16
R16
C9
C9
JHS808
R17
R19
R22R3
JHS808
R17
R19
R22R3
P78868
R18
C14
P78868
R18
C14
R21
R21
Yellow Purple Black Brown Brown
Yellow Purple Black Gold Brown
Yellow Purple Black Red Brown
Brown Black Black Brown Brown
C15
S
T
OutJInJ
Brown Black Black Black Brown
Red Red Black Black Brown
Green Brown Black Red Brown
Green Brown Yellow Gold
Brown Black Black Red Brown
C15
S
T
OutJInJ
Red Red Black Yellow Brown
Resistors have a low profile, sitting closer to the board than taller components,
R9 Resistor (4.7 kΩ)
R23 Resistor (47 Ω)
R1, R2 Resistors (47 kΩ)
R3, R5, R12, R16, R17 Resistors (1 kΩ)
R21 Resistor (100 Ω)
R15 Resistor (220 Ω)
R10 Resistor (51 kΩ)
R6, R19 Resistors (510 kΩ)
R7, R8, R13, R20, R22 Resistors (10 kΩ)
R4 Resistor (2.2 MΩ)
so install them first. Their locations are marked with numbers on the board.
D8
stewmac.com ©2017 Stewart-MacDonald page 4 of 12
Resistors are not polarized, so it doesn’t matter which lead goes in which
eyelet. They can be installed in either direction.
Step 2: Install six diodes
JHS Pedals Kit
For Stew Mac
R10
R11
D5
D4
R9
R8
R6
R7
S
C5
T
DC Jack
R23
R1
C4
R2
R12
C8 C12
U1
D2
D7
D3
R13
C7
Q1 Q2
D8
R14
C10
C6 C13
R15
R4R5 R20
D1
C2
JHS808
C3
P78868
C1
R18
D1 Diode (P6KE22A)
D2, D3, D7 Rectiers
D4, D5 Red LEDs (5mm)
C14
R16
R17
R19
C9
R21
S
T
R22R3
OutJInJ
Diodes are polarized, so they need to be installed in the correct orientation.
C15
Note the stripe around one end: this marks the negative (minus) lead of the
diode. On the circuit board, the printed outline of the diodes also shows this
stripe. Install each diode so that its stripe matches the direction shown on
the circuit board.
D1 is a larger sized P6KE22A diode. D2, D3, D7 are all 1N4148 rectifiers. Solder
them in their marked locations now.
The leads on diodes sometimes vary in diameter. If the leads don’t fit into
the eyelets in the circuit board, trim them at a steep angle to create sharp
points that fit into the holes.
Next install the two red LED (Light Emitting Diodes) clipping diodes, D4 and
D5, on their location marks. These are also polarized and need to be installed
in the correct orientation. On the circuit board, their location marks indicate
a flat on one side. This matches the slight flat on one side of the LED diode.
Install them so the flat on the board matches the flat on the LED.
stewmac.com ©2017 Stewart-MacDonald page 5 of 12
JHS Pedals Kit
Capacitors (.1 µF)
For Stew Mac
R11
D5
D4
R9
R8
R6
R7
S
C5
T
DC Jack
R10
D7
D3
C7
Q1 Q2
D8
R23
C4
R12
C8 C12
D2
R13
R14
C10
C6 C13
R15
C2
R1
C3
C1
R2
U1
R4R5 R20
Step 3: Install fourteen capacitors
D1
JHS808
P78868
R18
R16
R17
R19
C14
The four capacitors shown above are polarized, and have to be installed in
100uF
10uF
C3, C4 Capacitors (100 µF)
C1, 15 Capacitors (10 µF)
the correct orientation. Note the white stripe running the length of each cap;
C9
R21
S
T
R22R3
OutJInJ
this identifies the negative (minus) lead. On the circuit board, the circle for
C15
this cap’s location has a thicker line on one side: insert the capacitors with
their stripe facing that side. (On polarized caps of this type, there’s a second
way to identify the minus lead: it is the shorter of the two leads.)
JHS Pedals Kit
For Stew Mac
R11
D5
D4
R9
R8
R6
R7
S
C5
T
DC Jack
C4
R10
D8
C8 C12
D2
D7
D3
C7
C6 C13
Q1 Q2
R23
R1
C3
R2
R12
U1
R13
R14
C10
R15
R4R5 R20
D1
C2
JHS808
P78868
C1
R18
C14
R16
R17
R19
C9
R22R3
R21
C15
S
T
OutJInJ
NPO 51J
27nJ63
C7 Capacitor (.047 µF)
47NJ
C8 Capacitor (51 pF)
C2, C12, C14
.1J63
C9, C10 Capacitors (.22 µF)
.22J63
C6, C13 Capacitors (1 µF)
1J63
C5 Capacitor (.027 µF)
The remaining capacitors are not polarized. Solder these caps in place
facing either direction.
stewmac.com ©2017 Stewart-MacDonald page 6 of 12
Step 4: Install the operational amplifier
JHS Pedals Kit
For Stew Mac
R11
D5
D4
R9
R8
R6
R7
S
C5
T
DC Jack
R10
D7
D3
C7
47nJ
Q1 Q2
D8
R23
C4
R12
C8 C12
D2
R13
R14
C10
.22J63
C6 C13
1J63
R15
C2
.1J63
R1
C3
C1
R2
.1J63
U1
R4R5 R20
D1
R16
C9
.22J63
1J63
JHS808
R17
R19
R22R3
P78868
R18
C14
.1J63
R21
U1 Low noise op-amp (4558P 500nA)
U1.2 socket for op-amp
The operational amplifier consists of two parts: the op-amp itself (U1), and
the socket it plugs into (U1.2).
C15
You’ll solder the socket first, then install the op-amp in the socket.
S
T
OutJInJ
The op-amp has to be oriented correctly in order to function properly. There
are two indicators on the circuit board to guide you in positioning it:
1. The rectangular U1 position marker has a small notch at one end. Align the
similar notch in socket U1.2 when installing the socket.
2. The U1 position marker has a dot in one corner. There is a dot molded into
the corner of op-amp U1. Align these corners when pressing the op-amp
into place.
Solder socket U1.2 to the board. The op-amp U1 then snaps in without solder.
This feature allows you to try different op-amps with no soldering.
JHS Pedals Kit
For Stew Mac
R11
D5
D4
R9
R8
R6
R7
S
C5
T
R10
Step 5: Install two transistors
DC Jack
C4
C8 C12
D2
D7
D3
C7
47nJ
.22J63
C6 C13
1J63
Q1
D8
R23
.1J63
R1
C3
C1
R2
R12
.1J63
U1
U1
R13
R14
C10
R15
R4R5 R20
D1
C2
R16
.22J63
1J63
C9
JHS808
R17
R19
Q2
R22R3
P78868
R18
C14
.1J63
R21
Q1, Q2 Transistor (2n3904)
Q1 and Q2 are 2n3904 JFET* transistors. They are directional, and need to
be installed in a specific orientation. Note that they have a flat side. On the
circuit board, their location outlines also have a flat side. Install the transistors
to match these outlines.
*JFET: Junction Gate Field-Effect Transistor
C15
S
T
OutJInJ
stewmac.com ©2017 Stewart-MacDonald page 7 of 12
Step 6: Install the mini toggle switch
On-on solder lug toggle
The three-position mini toggle switch installs on the back of the board, and
there is no location marker printed. Solder the switch to the three large eyelets
pictured, making sure it’s flat and square to the circuit board.
The switch is not directional, so it works equally well turned in either direction.
Step 7: Install the control pots
Break o this index pin on all 3 pots.
R18 Volume pot (100 kΩ, linear taper)
Adhesive foam tape
(Goes on back of the pots)
R11 Drive pot (500 kΩ, linear taper)
Adhesive foam tape
R14 Tone pot (5 kΩ, linear taper)
The last components to go onto the circuit board are the three control pots.
They install on the back of the board. Each pot has three connecting lugs; the
illustration in Step 8 shows the three pots in position on the board.
stewmac.com ©2017 Stewart-MacDonald page 8 of 12
Each pot has an index pin protruding from the case. Break off this pin before
installation, so the pot will mount flush against the pedal case. Needle nose
pliers work well for removing the pins.
Use the adhesive foam tape to insulate the back of the pot from the soldered
leads of the other parts. Solder the pot in place, making sure it sits flat on the
back of the board.
Step 8: Install the footswitch, then the ribbon cable
B500K B1K
B100K A500K
B5K
Footswitch
Ribbon cable
JHS Pedals Kit
For Stew Mac
R11
D5
D4
R9
R8
R6
R7
S
C5
T
R10
D8
DC Jack
C4
C8 C12
D2
D7
D3
C7
47nJ
.22J63
C6 C13
1J63
Q1
R23
.1J63
R1
C3
C1
R2
R12
.1J63
U1
U1
R13
R14
C10
R15
R4R5 R20
D1
C2
R16
.22J63
1J63
C9
JHS808
R17
R19
Q2
R22R3
P78868
R18
C14
.1J63
R21
C15
S
T
OutJInJ
Install the footswitch on the back of the circuit board. The switch lugs will
fit in only one of two directions; either orientation works fine. Insert the lugs
through the nine eyelets so the switch sits flush, making contact all around.
JHS Pedals Kit
For Stew Mac
R11
D5
D4
R9
R8
R6
R7
S
C5
T
R10
DC Jack
R23
C4
R12
C8 C12
D2
D7
D3
R13
C7
47nJ
Q1
R14
C10
.22J63
C6 C13
1J63
R15
C2
.1J63
R1
C3
C1
R2
.1J63
U1
U1
R4R5 R20
D1
R16
C9
.22J63
1J63
JHS808
R17
Q2
R22R3
P78868
R18
C14
R19
.1J63
R21
Solder one lug and let it cool. This holds the switch in place while you solder
the remaining lugs.
Next, install the ribbon cable. Insert the cable leads through the front of the
board, and solder them in place on the back.
Step 9: Install the lead wires, cut the board
Lead wire, cut into six 2" lengths
Cut the lead wire into six 2" lengths for the input, output, and power jacks.
Strip the insulation on the ends and thread them through the front of the
board. Solder them on the back of the board.
Now you can cut the switch portion of the board away from the main board.
Small wire cutters make quick work of this, and a small saw also works.
C15
S
T
OutJInJ
D8
stewmac.com ©2017 Stewart-MacDonald page 9 of 12
Step 10: Install the LED mounting bezel and the two jacks
LED mounting bezel
Two jacks
Install the plastic mounting bezel for the LED indicator by pressing it in
from the outside, through the top of the case. Spread the tabs open inside
the case to hold it in place.
Install the input and output jacks on the sides of the case. Keep the lugs
facing up so you’ll have easy access when it’s time to solder them.
R11
D5
D4
S
D8
JHS Pedals Kit
For Stew Mac
R10
R9
R8
R6
R7
C5
T
DC Jack
C4
C8 C12
D2
D7
D3
C7
47nJ
C6 C13
1J63
Q1
R23
R1
C3
R2
R12
U1
U1
R13
R14
C10
.22J63
R15
R4R5 R20
.1J63
C1
.1J63
C2
D1
.22J63
1J63
Step 11: Mount the circuit board in the case
The main circuit board is held in place by the control pots and mini toggle
JHS808
P78868
R18
C14
R16
R17
R19
.1J63
C9
C15
R21
Q2
S
T
R22R3
OutJInJ
switch.
Install their shafts through the top of the case, and thread flat washers onto
them on the outside. Install the mounting nuts so they are good and snug,
but take care not to overtighten.
stewmac.com ©2017 Stewart-MacDonald page 10 of 12
Step 12: Install the LED in the mounting bezel
R11
D5
D4
S
D8
JHS Pedals Kit
For Stew Mac
R10
R9
R8
R6
R7
C5
T
DC Jack
C4
C8 C12
D2
D7
D3
C7
47nJ
C6 C13
1J63
Q1
R23
R1
C3
R2
R12
U1
U1
R13
R14
C10
.22J63
R15
R4R5 R20
.1J63
D1
C2
JHS808
P78868
C1
R18
.1J63
C14
R16
R17
R19
.1J63
C9
.22J63
1J63
C15
R21
Q2
S
T
R22R3
OutJInJ
Like some of the caps and diodes, the D8 LED is polarized and has to be installed in a specific direction. One side of the diode has a flat edge, indicating
the negative lead. Another indication is that the negative lead is shorter than
the positive. The circle marking the D8 location on the switch circuit board
has a corresponding flat to indicate the mounting orientation.
Insert the LED into the bezel. It will be held in place by soldering it to the
D8 LED (5mm)
switch circuit board in Step 13, but for a more secure mount you can run a
bead of clear silicone adhesive around the LED and bezel.
Step 13: Install the footswitch
JHS Pedals Kit
For Stew Mac
R11
D5
D4
S
T
R10
R9
R8
R6
R7
C5
D8
DC Jack
C4
C8 C12
D2
D7
D3
C7
47nJ
C6 C13
1J63
Q1
R23
R1
C3
R2
R12
U1
U1
R13
R14
C10
.22J63
R15
R4R5 R20
.1J63
C1
.1J63
C2
D1
.22J63
1J63
1/8"
Thread one of the nuts onto the footswitch, leaving
JHS808
P78868
R18
C14
R16
R17
R19
.1J63
C9
C15
R21
Q2
S
T
R22R3
OutJInJ
Carefully install the switch so the legs of the diode feed through the D8 holes
on the switch circuit board.
Place the flat washer on the switch shaft on the top of the case. As you tighten
the remaining nut on the switch, hold the switch circuit board inside the case
so that it doesn’t rotate.
a 1/8" gap between it and the switch housing. Place
the split lock washer on next.
Solder the D8 LED and trim the leads.
stewmac.com ©2017 Stewart-MacDonald page 11 of 12
Step 14: Install the DC power connector
JHS Pedals Kit
For Stew Mac
R11
D5
D4
S
T
R10
R9
R8
R6
R7
C5
D8
DC Jack
C4
C8 C12
D2
D7
D3
C7
47nJ
C6 C13
1J63
Q1
R23
R1
C3
R2
R12
U1
U1
R13
R14
C10
.22J63
R15
R4R5 R20
.1J63
C1
.1J63
C2
D1
.22J63
1J63
Positive
JHS808
P78868
R18
DC power connector
Negative
Insert the DC power connector so the negative lug is facing up, and tighten
it in place. The negative lug is the one with the largest metal tab.
C14
R16
R17
R19
.1J63
C9
C15
R21
Q2
S
T
R22R3
OutJInJ
Solder the installed leads from the circuit board to the jack. Where they attach
to the board, the positive lead is on the the right and the negative is on the left.
Step 15: Wire the input/output jacks
JHS Pedals Kit
For Stew Mac
R11
D5
D4
S
T
R10
R9
R8
R6
R7
C5
D8
DC Jack
C4
C8 C12
D2
D7
D3
C7
47nJ
C6 C13
1J63
Q1
R23
R1
C3
R2
R12
U1
U1
R13
R14
C10
.22J63
R15
R4R5 R20
.1J63
C1
.1J63
C2
D1
.22J63
1J63
On the circuit board, the input and output jack leads are labeled InJ and OutJ.
JHS808
P78868
R18
C14
R16
R17
R19
.1J63
C9
C15
R21
Q2
S
T
R22R3
OutJInJ
The leads are also labeled T for tip, and S for sleeve. Looking at a jack, you’ll
see that the sleeve lug is attached to the threaded shaft. The tip lug connects
to the spring metal piece that contacts the tip of a guitar cord.
Solder these four leads as shown to finish the assembly.
Screw the bottom onto the case and add the control knobs.
Plug in and rock out!
Here’s how to use the JHS808:
Requires 9V DC
center-negative power
Overall output level
Volume
Tone
Adjusts the top end
Output
supply (not included)
Drive
Dial in more
or less overdrive
3-way gain switch
Three tone options:
Up: LED clipping
•
Middle: Open boost
•
Down: Silicon clipping
•
stewmac.com ©2017 Stewart-MacDonald page 12 of 12
Footswitch
On/O
Input
LED Indicator
On/O
Loading...