RYO Optodist User manual

Ljunggren Audio
Roll Your Own
Optodist
Version: Optodist/VCA 1.0
and Optodist/VCA 1.1
Bill Of Material
Changes from version 1.0 to 1.1
•The unused R8 resistor footprint is removed.
•The holes for the pototentiometer housing pins is enlarged to accomodate oth
standard 9mm Alpha and custom pots.
•Square instead of round pads on the jack housing pins.
•Different PCB colour.
Please note: Text in red (same type of red as this text)
indicates errors in the photos taken before final
assembly instructions were written. These errors will be
adressed in the next version of the assembly manual.
TYPE PART VALUE PCS NOTE
Resistor R11,R12 10R 2
Resistor R5,R10 1K 2
Resistor R13,R14 10K 2
Resistor R1,R9 68K 2
Resistor R2 100K 1
Resistor R3 100R 1
Resistor R4 4. M 1
Diode D2,D3 SB130 2 or 1N5818. Schottky power polarity protection
Capacitor C3,C4,C5,C6,C10,C11 100nF 6 Ceramic X R 2.5mm
Capacitor C2,C9 100pF 2 Ceramic C0G 2.5mm
IC Socket IC1,IC2 8 pin 2
OpAmp IC1,IC2 TL0 2 2 or TL082
LDR1 x2, LDR2 x2 2 pin 4 One for each side of the optocouplers.
Optocoupler LDR1,LDR2 SR2/SR3 2 Silonex NSL-32SR2 or NSL-32SR3 ”vactrol”
Electrolytic C ,C8 2 2mm pin pitch, 5mm dia, 5mm height
Transistor Q1 BC55 B 1
Transistor Q2 BC54 B 1
Trimmer TRIM1 2K 1 Gain range calibration
Jack J1,J2,J3 3.5mm 3 PJ301BM
Rotary Pot. POT1 100K lin 1 CV Att.
Rotary Pot. POT2 22K lin 1 Or 25K lin. Gain
Rotary Pot. POT3 100K log 1 Signal in Att.
Switch SW1 SPDT 1 On-On
LED D1 Orange 1 3mm
LED D4,D5,D6,D Green 4 3mm, LED limiter, other colours may be used.
Power header POWER 10 pin 1 boxed
Knobs Small fluted skirtless cream 3
Screws Black, Pozi M3x6 2 Mounting screws
PCB 1
Faceplate PCB material (FR4) black 1
Power cable Eurorack power cable 1 10pin ↔ 16pin
If you want your Optodist to close better for VCA duties use 10K on
R9. However, doing this will lessen the distortion effect.
Optocoupler
socket
10µF

Assem ly instructions
Empty PCB bottom Optodist 1.0
Empty PCB top Optodist 1.0
Empty PCB bottom & top Optodist 1.1

Step 1
Solder resistors. Resistors are not sensitive to mounting direction.
R1 68K, R 100K, R9 68K
R8 skip this one, R13 10K, R14 10K
R8 is unnecessa y but p esent in all photos, don't solde it at all.
On ve sion 1.1 this is emoved.
R5 1K, R10 1K
R11 10R, R1 10R

R3 100R
R4 4.7M
Step 2
Solder reverse polarity protection diodes. The stripe on the diodes must e on
the same side as indicated in the silk screen.
D SB130, D3 SB130

Step 3
Solder ceramic capacitors. Ceramic capacitors are not sensitive to mounting
direction.
C3 100nF, C4 100nF, C5 100nF, C6 100nF, C10 100nF, C11 100nF
C 100pF, C9 100pF
Step 4
Solder sockets. Match the IC sockets indent (pin 1) with the silk screens.
IC1, IC sockets. IC's will be mounted late .
LDR1, LDR sockets. Not sensitive to mounting di ection. Optocouple s will be mounted late .

Step 5
Solder Electrolytics. Long leg is + (anode).
C7 10µF, C8 10µF
Step 6
Solder transistors. Match the curved side with the silk screen.
Q1 BC557B
Q BC547B

Step 7
Solder trimmer. Only 3 of the 5 holes are used, the extra 2 holes are for fitting
trimmers with different appearence.
TRIM1 2K
Step 8
Solder jacks.
J1, J , J3

Step 9
Remove the nuts and washers from the potentiometers. Cut off the small
metal ta sticking out indicated y a red circle elow and solder them in place.
Please pay attention that POT1, POT2 and POT3 is not placed in a
linear order. The order from left to right (or ottom to top) is POT1,
POT3, POT2.
POT1 100K linea
POT 22K linea o 25K linea
POT3 100K loga ithmic

The following 2 steps (switch and LED's) can e done at the same time if you
wish.
Step 10
Remove the nuts and washers on the switch. The nuts are very similar looking
to the jack nuts ut they are not the same. The jacks nuts will not fit on the
switch ut the switch nuts will fit on the jacks so e careful not to mix them up
with each other.
Mount the switch without soldering it.
Mount the panel in the places shown in the picture a ove. You don't need to
tighten the nuts very hard, use your hands, no tools needed.

If you have Alpha potentiometers like the one on the
left you place one washer under the panel and one
nut over the panel.
The last kits with theese pots were shipped in May
2014 and is long gone y now.
If you have custom potentiometers like the one on the
right you place two washers and one nut under the
panel and one washer and one nut over the panel.
This is what is included in our kits after May 2014.
Now solder the switch in place and remove the panel afterwards.
SW1

Step 11
D4, D5, D6, D7 (LED limite ), D1 (o ange)
The long leg of the LED's (anode, +) goes in the square hole.
Put the LED's in place (don't solder yet) and temporary mount the panel the
same way as in the previous step. Carefully flip the module over.

Correct the LED positions with your hands making sure each LED has slotted
into their respective panel hole. Solder them in place.
Step 12
Solder the keyed oxed power header. Pay extra attention to the direction. The
triangle (pin 1) must e at the -12V side. In the picture elow you can see the
direction of the keyed opening in the oxed header.
POWER

Step 13
Mount the IC's and optocouplers.
The IC's indent or dot marking pin 1 must match the silk screen direction.
Be careful not to cut the legs too short on the optocouplers. Make sure the
Optocouplers dot match the dot/ evel marking in the silk screen.

Step 14
Mount the panel. Use 8 mm wrench socket for the jacks and switch and 10 mm
for the potentiometers.
Switch: Only use one of the originally attached switch nuts and none of the
original switch washers. Instead use the same washer model as for the jacks
(included in the switch ag). No washers under the panel.
Potentiometers: Use the washers that was originally attached to the
potentiometers under the panel and the nut over the panel.
Jacks: No washers under the panel. One washer and one nut per jack over the
panel.
Step 15
Mount the kno s on the potentiometers.

Step 16
Mount the power ca le. Red stripe at -12V.
Finished module!

Cali ration
1.
Patch an audio signal with a relatively clean waveform that is easy to hear
when clipping starts on, for example a sine. Listen to the audio signal.
2.
Turn up Gain fully CW (clock wise, right) position.
Turn up Signal In to fully CW (clock wise, right) position.
Turn down Gain CV fully CCW (counter clock wise, left) position.
3.
Adjust trimmer until you are satisfied with the maximum gain amount. The
output will e much louder with the LED limiter off than on.