Lithium Grim Autowah Instruction Manual

1
Autowah
Building instructions
V1.1

2
Table of contents
Components ............................................................................................................................................ 3
General guideline for components.......................................................................................................... 4
General building tips ............................................................................................................................... 4
Modifications........................................................................................................................................... 5
Offboard wiring ....................................................................................................................................... 5
Troubleshooting ...................................................................................................................................... 7
Schematic ................................................................................................................................................ 8
Read this entire manual thoroughly before you start to building the effect! Especially the
Building and Modification part. Decide before building the effect which mods you want to try so
that you do not need to desolder parts later.

3
Components
C1
22n
R1
5K1
R17
10k
D1
1N4148
C2
68n
R2
330R
R18
20k
D2
1N4148
C3
220n
R3
330R
R19
4M7
D3
LED
C4
8n2
R4
1M
R20
47R
D4
1N5817
C5
22n
R5
10k
R21
47k
D5
1N4001
C6
22n
R6
1M
R22
47k
D6
1N4148
C7
100u
R7
330R
R23
10k
C8
2u2
R8
6k8
R24
10k/20k
IC1
LM13700
C9
1u
R9
4M7
R25
3k3
IC2
TL074
C10
100n
R10
20k
R26
3k6
REG1
LM78L05
C11
1u
R11
20k
R27
4k3
C12
100n
R12
330R
R28
4k7
R13
330R
R29
100k
VR1 (RESONANCE)
B50k (lineair)
Q1
BC550C
R14
4k7
R30
1k
VR2 (SENSITIVITY)
B100k (lineair)
Q2
BC550C
R15
4k7
R31
6k8
VR3 (BIAS)
B50k (lineair)
Q3
2N5457
R16
6k8
R32
6k8
VR4 (DECAY)
C1M (reverse log)

4
General guideline for components
Capacitors: All values under 1nF should be ceramic disks. From 1nF up to 1uF should be MKT
or SMF (metal film capacitors). For over 1uF use electrolyte caps 16V+ rated and watch out
for polarity! C9 is also electrolyte.
Resistors: use 1% metal film for the best results.
Socket all IC’s and transistors. This way you can easily mod them or replace them if they
brake.
General building tips
Soldering this board can be moderately complicated for some people since the solder pads can be
very close together. Use a magnifying glass to make the job more easy.
Start by soldering the resistors and diodes. Next, solder the sockets for the IC’s and transistors. For
the transistors you can buy a 20 pin SIL socket and cut of the pins you need. IC1 needs a 16 pin DIL
socket and IC2 needs a 14 pin DIL socket. If you want to socket D6 (see MODS below) than solder the
socket now. Next you can solder the MKT capacitors and finish by soldering the electrolyte
capacitors. Note that C8 and C11 fit both MKT as well as electrolyte but watch the polarity! If you
look at the picture on page 3, the positive side is marked with a + and the hole above of the + is also
positive. Only the top most hole for both C8 and C11 are negative (-). Now you can place the IC’s and
transistors. The white triangle on the IC’s point to where pin 1 of the IC should be inserted.
Note: Q1 and Q2 are both displayed misprinted on the PCB. Rotate both transistors 180 degrees to
correctly place them.
Besides the components mentioned in the table on the first page, you will need:
2 input jacks. 2 mono jacks if you are not going to use a battery clip, only 9V adapter, or 1
mono (for output) and 1 stereo jack (for input) if you will be using a battery clip.
3PDT footswitch (9 pins) and a LED to build in your casing (see page 5).
2,1mm DC jack (isolated).
9v battery clip (optional).
22 gage stranded hook-up wire
Hammond 1590BB case (or similar) in your favourite colour.

5
Modifications
You can try to replace D6 (1n4148) with a 1N34 for smoother operation. You can also
experiment with other diodes. To do this you can solder 2 IC pins in the holes of D6 so you
can easily mount different diodes.
It’s been reported that the use of an 1uF electrolyte cap in C8 instead of a 2u2 electrolyte
makes things more smooth.
Change R18 from 20k to 47K for more linear sensitivity response.
If you are using a different LED than you can alter the value of R25 accordingly. Generally 3k3
will be enough for most bright LEDs, but a bright green one might need a 680R to function
correctly. Please check which value suits your LED best before using it.
The original uses a LM324 instead of a TL074, but I personally prefer the TL074.
Because there is no 7k9 resistor in exsistance, I chose to split it in 2 resistors (R26=3k6,
R27=4k3). But as the resitor value is not that important because the BIAS (VR3) can
compensate for it, you could choose to use a 7k5 or 8k2 and compensate by turning the Bias
pot a bit more up or down. To do so, insert the 7k5/8k2 in the bottom pad of R27 and the top
pad of R26

6
Blue = pin 1
White = pin 2
Yellow = pin 3
Offboard wiring
Tip
Tip
Ring
Ring
Output JackInput Jack
Cathode (short leg)
Anode (long leg)
Footswitch
Sleeve
Notice that in the “off” position the effect input is connected to ground to prevent possible
oscillation. If you are using your own 3PDT PCB then you should not install R25 and only connect the
+9V side of your 3PDT PCB to the R25 hole next to the +9V on the autowah PCB.

7
Troubleshooting
All PCB’s have been e-tested 100% so there should not be a connection problem on the PCB itself.
The board is not working (at all), what now?
Check that you oriented the capacitors, IC’s ,transistors and diodes the right way. MKT
capacitors and resistors do not need to be oriented. Also check if your 9V is plugged in
correctly (and/or soldered correctly on the board).
Double and triple check your soldering! A lose or cold solder can be really bad for your board.
Check if you used the correct values of the components. For resistors you can look here:
http://www.diyaudioandvideo.com/Electronics/Color/
Replace the IC’s and transistors, one might be defective. Before doing that first unplug the 9V
and wait 5 seconds.
Check that you have good/high grade components. A lot of Chinese sourced parts are fakes
(especially high end opamps) so be careful that you source your parts from reliable suppliers.

8
Schematic
CX
C10
C3
C5
C2
C6
C4
C1
C6