Build Your Own Clone Message Board

I'm attempting to build an opticomp from scratch, and am having some issues I can't seem to diagnose. Bypass works, the LED turns on, and I do get a signal when the pedal is engaged that sounds almost identical to the bypass (slightly less low end). The problem is I get a harsh clipping when playing loud notes. I also don't get any compression, and the sustain knob does nothing. The volume knob works as intended.

Bear in mind, I made this PCB based on the images in the BYOC opticomp instructions without any modifications, and I bought all the parts from third party sites. I have checked the connection of every component's connection to match the schematic. All is good as far as I can tell.

When I first soldered everything and plugged a guitar in, it had an odd, very faint clipped sound. I noticed that the PCB had an error with one of the transistors, which I corrected (unless I'm mistaken?). I was using the schematic as my reference. See below:


I breadboarded this circuit according to the schematic prior to soldering into the PCB and it worked great. The issue only happened when everything was soldered into the PCB.

I got the parts from Mouser and Small Bear. Some had to be similar replacements:
Opticouplers
Transistors
IC

I bought duplicates of almost all of the components (except the transistors...), so I've swapped out the Optocoupler, IC, and have tried the capacitor arrangement mentioned for a bass compressor. No differences yet in sound.

Based on the symptoms, does anything stand out? Really stumped on this one!

**Disclaimer about this images -- I only soldered components to the side of the board that had a trace so i could more easily desolder if necessary. Also, I have a couple components that still have uncut legs since I've been testing replacements.
http://imgur.com/a/FsenS

Thanks!

The BYOC kits use two sided PCB's with through-hole eyelets for front-to-back connections. Have you identified which eyelets have trace connections on both sides of the board and soldered the component leads on both sides to insure complete circuits?

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“My favorite programming language is SOLDER” - Bob Pease (RIP)

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Yes, I've made sure any through hole connection that has a trace on either side is connected properly.

A new development: i hooked up a 100k pot + 1k resistor in series to replace the 4k7 resistor that connects to the optocoupler. While getting this properly soldered I got a lot of mixed results, and things changed as I wiggled the connection of the 500k pot around. Now that everything is soldered properly, it behaves a little differently, but still not properly. Turning the 500k pot all the way to the left increases the volume/gain a lot and eventually sounds like a distortiom pedal.

There was a moment where fiddling with the newly placed 100k pot and 500k pot started to sound like a compressor, but now I can't reproduce it. Any tips on what I can test in order to isolate the problem? It's starting to get hard to troubleshoot because too many variables are changing.

I suspect I may have fried the optocoupler. How can I test it?

I'm trying to follow this but as you said , there are a lot of moving parts. Pictures always help.

I wouldn't worry about frying anything just yet.

Also, the optocomp compression is subtle until the last 1/4 of its rotation.

I'm out of town for a few days but when I get back I'll see if anything has changed and keep trying. I'll report back if I can make some progress.