Lithium Grim OmniWah Instruction Manual

OmniWah
Building instructions
v1.0

OmniWah v1.0
Manufacturers and product names are mentioned solely for circuit identification, and where applicable their trademarks are the
property of their respective owners who are in no way associated or affiliated with the author. No cooperation or endorsement
is implied.
2
Table of contents
PCB layout ............................................................................................................................................... 3
Build options............................................................................................................................................ 4
Vintage Wahs ...................................................................................................................................... 4
Modern signature Wahs...................................................................................................................... 4
Components ............................................................................................................................................ 5
Modifications........................................................................................................................................... 7
Mix and match..................................................................................................................................... 7
Sweep board........................................................................................................................................ 7
Mechanical Sweeprange mod ............................................................................................................. 7
Build sequence ........................................................................................................................................ 8
Off board wiring ...................................................................................................................................... 9
Potentiometers.................................................................................................................................... 9
Miniswitches.................................................................................Fout! Bladwijzer niet gedefinieerd.
Footswitches and stargrounding....................................................................................................... 10
Troubleshooting .................................................................................................................................... 11
Schematic .............................................................................................................................................. 12
Read this entire manual thoroughly before you start building the effect! There are some available
options and mods and you should choose which one you want to incorporate before starting your
build.
Last update: 10-12-2017

OmniWah v1.0
Manufacturers and product names are mentioned solely for circuit identification, and where applicable their trademarks are the
property of their respective owners who are in no way associated or affiliated with the author. No cooperation or endorsement
is implied.
3
PCB layout
Dimensions: 50 mm x 50 mm
1.97 inch x 1.97 inch

OmniWah v1.0
Manufacturers and product names are mentioned solely for circuit identification, and where applicable their trademarks are the
property of their respective owners who are in no way associated or affiliated with the author. No cooperation or endorsement
is implied.
4
Build options
This PCB can be used to mimic a wide range of vintage and modern wahs. In the components section
the following abbreviations will be used:
Vintage Wahs
Thomas: Thomas Organ CryBaby
Grey: Vox Grey Wah
V847: Vox v847 Wah
Color: Colorsound Inductor wah
Shin: Shinei Wah
BG-1: Maestro Boomerang Wah BG-1
Modern signature Wahs
JH-1: Dunlop JH-1 Hendrix Crybaby
ZW-45: Dunlop ZW-45 Wylde Crybaby
DB-1: Dunlop DB-1 Dimebag Crybaby
JC-95: Dunlop JC-95 Jerry Cantrell Crybaby
Omni: Modded Dunlop GCB-95 Crybaby
In the components section you will find the components needed for the different configurations.
When it says “jump”, there is no component to be place but instead you’ll need to connect both pad
of the component with a jumper wire (eg a spare piece of lead wire you get when cutting a resistor
to size). When it says “jump 1-2”, then you’ll need to connect pad 1 to pad 2 of the component with
a jumper wire. With “jump 2-3” you’ll need to connect pad 2 to pad 3 of the component with a
jumper wire.
A dash (“-“) means there is no component to be placed at that spot for that type of wah.
P1-P5 can be either an internal or external potentiometers. When you want to use the controls
during play, I suggest you make them external by using an Alpha 16mm pot meter. The pads are
marked accordingly to match the pins of the potentiometer. Else us a 6 mm PCB potentiometer.
P1 and P2 can be either a potentiometer or a single resistor depending on the type of wah you want
to build. Only for the Omni version you’ll need to add the potentiometer. For all other versions, you
can use the added special extra pads (marked in red below) on the board for the fixed (or jumped)
value resistor.

OmniWah v1.0
Manufacturers and product names are mentioned solely for circuit identification, and where applicable their trademarks are the
property of their respective owners who are in no way associated or affiliated with the author. No cooperation or endorsement
is implied.
5
Components
Thomas
Grey
v847
Color
Shin
BG-1
C1
-
-
-
-
-
-
C2
-
-
-
-
-
-
C3
-
-
-
-
-
-
C4
jump
jump
jump
jump
5n
4n7
C5
-
-
-
-
-
-
C6
10n
10n
10n
10n
jump
jump
C7
3u9
4u7
4u7
10u
10u
6u
C8
220n
220n
220n
220n
200n
1u
C9
-
-
-
-
-
-
C10
220n
220n
220n
220n
200n
1u
C11
-
-
-
-
-
-
C12
-
-
-
-
-
-
C13
10n
10n
10n
10n
30n
10n
D1
-
-
-
-
-
-
J1
jump
jump
jump
jump
jump
jump
L1
500mH
250mH
500mH
550mH
500mH
500mH
P1
68k
68k
68k
100k
30k
47k
P2
470R
470R
510R
jump
470R
120R
P3
Jump 2-3
-
Jump 2-3
Jump 2-3
Jump 2-3
Jump 2-3
P4*
B100k
B100k
B100k
B100k
B50k
B25k
P5
Jump 1-2
Jump 1-2
Jump 1-2
Jump 1-2
Jump 1-2
Jump 1-2
Q1
-
-
-
-
-
-
Q2**
5517
BC150
MPSA18
BC184
2SC828
BC109C
Q3**
2N2925
BC150
MPSA18
BC167B
2SC828
BC109C
R1
-
-
-
-
-
-
R2
-
-
-
-
-
-
R3
-
-
-
-
-
-
R4
jump
jump
jump
jump
jump
jump
R5
-
-
-
-
-
-
R6
1k5
1k5
1k5
1k6
1k2
1k2
R7
22k
22k
22k
22k
22k
10k
R8
470k
470k
470k
470k
470k
-
R9
470k
470k
470k
470k
470k
1M5
R10
82k
82k
100k
-
-
-
R11
33k
-
33k
100k
100k
47k
R12
-
-
-
-
-
-
R13
-
-
-
-
-
620k
R14
-
-
-
-
-
-
R15
1k
1k
1k
jump
1k2
jump
R16
10k
10k
10k
10k
10k
8k2
SW1
-
-
-
-
-
-

OmniWah v1.0
Manufacturers and product names are mentioned solely for circuit identification, and where applicable their trademarks are the
property of their respective owners who are in no way associated or affiliated with the author. No cooperation or endorsement
is implied.
6
JH-1
ZW-45
DB-1
JC-95
Omni
C1
10n
10n
10n
10n
10n
C2
22p
22p
22p
22p
22p
C3
100n
100n
100n
100n
100n
C4
jump
jump
jump
jump
jump
C5
100u
100u
100u
100u
100u
C6
10n
10n
10n
10n
10n
C7
4u7
4u7
3u9
3u9
3u9
C8
220n
220n
220n
220n
220n
C9
22n
-
-
-
-
C10
220n
220n
220n
220n
220n
C11
-
-
-
-
-
C12
-
-
-
-
-
C13
10n
22n
10n
12n
10n
D1
ZL9M3
-
-
-
ZL9M3
J1
-
-
-
-
-
L1
500mH
500mH
535mH
500mH
500mH
P1
68k
68k
68k
68k
B100k
P2
390R
390R
470R
390R
B1k
P3
Jump 2-3
Jump 2-3
Jump 2-3
Jump 2-3
B100k
P4*
B470k
B100k
B100k
B100k
B100k
P5
Jump 1-2
Jump 1-2
B5k
B5k
B10k
Q1
MPSA13
MPSA13
MPSA13
MPSA13
MPSA13
Q2**
MPSA18
MPSA18
MPSA18
MPSA18
MPSA18
Q3**
MPSA18
MPSA18
MPSA18
MPSA18
MPSA18
R1
-
-
-
-
1M
R2
2M2
2M2
2M2
2M2
2M2
R3
1M8
1M8
1M8
1M8
1M8
R4
1k
1k
1k
1k
1k
R5
10k
10k
10k
10k
10k
R6
1k5
1k5
1k5
1k5
1k5
R7
22k
22k
22k
22k
22k
R8
470k
470k
470k
470k
470k
R9
470k
470k
470k
470k
470k
R10
82k
82k
82k
82k
82k
R11
82k
33k
33k
33k
10k
R12
-
-
-
-
-
R13
-
-
-
-
-
R14
-
-
-
-
-
R15
1k
1k
1k
1k
1k
R16
10k
10k
10k
10k
5k1
SW1
-
-
-
-
-
Capacitors with values < 1nF are MLCC, values of 1nF –1uF are SMF and all values > 1uF are
Electrolyte. “B” means linear for potentiometers.
NB Wah pot tapers (P4) are not always linear!!

OmniWah v1.0
Manufacturers and product names are mentioned solely for circuit identification, and where applicable their trademarks are the
property of their respective owners who are in no way associated or affiliated with the author. No cooperation or endorsement
is implied.
7
Modifications
Mix and match
You could mix a few options of different versions to get your own custom effect. I think it would be a
good idea to add R1 (pull down resistor) and P2 (Gain) to all types. This way you can reduce the pop
when switching on the effect and add a gain control that influence the tone of the wah.
Also consider to experiment with different types of transistors. The described transistors can be
replaced with any 300-400 Hfe NPN transistor.
Sweep board
A nice added feature can be to add a sweep board to replace C13. You can use a rotary switch for the
for example a 2P5T so you can switch between 5 different values. The example below is just for
reference. You can always use different values then mentioned in the picture.
.001
.001
.001
.001
.001
To PCB top C13
To PCB bottom C13
10nF 22nF 33nF 47nF 68nF
Mechanical Sweeprange mod
If you are using an old crybaby shell, then you might want to remove the rubber underneath the heel
of the wah plate. Also you might want to cut about half of the front 2 rubbers off. This way the
sweeprange of the wah will increase dramatically. But be careful not to remove too much. Maybe cut
in stages and test.

OmniWah v1.0
Manufacturers and product names are mentioned solely for circuit identification, and where applicable their trademarks are the
property of their respective owners who are in no way associated or affiliated with the author. No cooperation or endorsement
is implied.
8
Build sequence
Soldering this board can be very complicated for some people since the solder pads are very close
together. Use a magnifying glass to make the job easier. The trick to soldering a PCB is to work from
small to big components. My building sequence suggestions in this section are based on the parts I
used myself. Sometimes some components are smaller (or bigger) so always use your own common
sense and change the order accordingly. Usually capacitors can differ a lot in size depending on their
rating and value.
Note: Do not blow on your solder in an attempt to cool it down. That can result in a bad join that
might corrode!
Start by soldering the jumpers where needed. Next, solder the resistors and Zener diode.
If you want to experiment with other transistors then you could socket them instead of soldering
them to the board. You’ll need a some 20 SIL sockets, break off the sockets and solder them to the
board. Now is the time to solder these sockets on the PCB. Place the transistors only once you are
finished with all soldering and off board wiring!
Note: Orientation of the transistors vary for each different type you use. For this reason I marked the
pinout on the board for your convenience. I also added a graphic of the rounded side of the
transistor. This is based on the vintage transistors. Eg. a MPSA needs to be rotated 180 degrees!
Always consult the datasheet of the transistor and orient accordingly.
Now continue by soldering the small capacitors (MLCC) then the small SMF, trimpots and then the
Electrolytes. Finish with soldering the inductor.
I suggest you now drill the holes in your enclosure (maybe a spare old crybaby shell) so you can use it
during the off board wiring.
Note: Really take some time to determine where to place the pots, switches, jacks and PCB in the
enclosure before you start drilling. Measure twice, drill once.
You are almost ready to rock, well… not really. The difficult part starts now.
Besides the components mentioned in the components table, you will need:
2 input jacks. 2 mono jacks if you are not going to use a battery but only the 9V adapter. 1
mono (for output) and 1 stereo jack (for input) if you will be using both a 9V battery and the
9V adapter.
1 x 3PDT footswitch (9 pins)
2,1mm DC jack (isolated).
9v battery clip (optional).
22 gage stranded hook-up wire.
A LED holder. This enables you to mount the LED in the enclosure.
Wah enclosure (new or used).

OmniWah v1.0
Manufacturers and product names are mentioned solely for circuit identification, and where applicable their trademarks are the
property of their respective owners who are in no way associated or affiliated with the author. No cooperation or endorsement
is implied.
9
Off board wiring
Potentiometers
In the pictures below you see the correct pin numbering of the pots (Alpha 16mm style).
Solder the wires accordingly and it is always a good idea to twist the wires together to create a sort
of extra shielding against external noise.
You can break off the pin I marked with the yellow circle with a small pair of pliers.
P1 Volume
P2 Gain
P3 Voice
1 2 3
P4 Wah
P5 Sweep

OmniWah v1.0
Manufacturers and product names are mentioned solely for circuit identification, and where applicable their trademarks are the
property of their respective owners who are in no way associated or affiliated with the author. No cooperation or endorsement
is implied.
10
Footswitches and stargrounding
Ring
Sleeve
Tip
Tip
Sleeve
Cathode (short leg)
Anode (long leg)
R led
Note that R led is a 4k7 resistors. You can change this value depending on the type of LED you use
but 4k7 is safe enough for almost all LEDs @ 9V.
It is now time to place your transistors in the sockets if needed. Connect everything, build it in your
enclosure and enjoy your effect!
The sleeve on the output jack is not connected on purpose. Make sure the output jack is in good
electronic contact with the enclosure else you can try and connect the sleeves of the input and
output together. If you test the unit outside of an enclosure you need to connect the output sleeve
to ground!

OmniWah v1.0
Manufacturers and product names are mentioned solely for circuit identification, and where applicable their trademarks are the
property of their respective owners who are in no way associated or affiliated with the author. No cooperation or endorsement
is implied.
11
Troubleshooting
All PCB’s have been 100% factory e-tested and out of every batch I receive I build an effect to double
check, so there should not be a connection problem on the PCB itself.
The board is not working (at all), what now?
Check if your 9V is plugged in correctly (and/or soldered correctly on the board). Pay special
attention to the polarity.
Check that you oriented the capacitors, IC’s ,transistors and diodes the right way. SMF, MKT
and ceramic capacitors as well as resistors do not need to be oriented. A likely sign of
incorrect capacitors and/or orientation is when an effect is sputtering, rumbling or
“motorboating”.
Check if you used the correct values of the components. For resistors you can look here:
http://www.diyaudioandvideo.com/Electronics/Color/
Double and triple check your soldering! A loose or cold solder can be really bad for your
board.
Replace the IC and/or transistors, one might be defective. Before doing that first unplug the
9V and wait for 5 seconds.
Check that you have good/high grade components. A lot of Chinese sourced parts are fakes
(especially high end opamps, audio capacitors, vintage diodes and transistors) so be careful
that you source your parts from reliable suppliers.

OmniWah v1.0
Manufacturers and product names are mentioned solely for circuit identification, and where applicable their trademarks are the
property of their respective owners who are in no way associated or affiliated with the author. No cooperation or endorsement
is implied.
12
Schematic