SOLVED Pro-10 Dual Overdrive issues

[Jazzwolf]

Hello all,

I am a bit of a novice to the pedal making game. I have made 4 pedals from aion effects and those all turned out well. This is my first PedalPCB.com pedal and I am having some issues. The Blue side (Left when looking down at top) gives me no sound at all when activated. This is likely a beginner issue on my part.

Things that work:

• I have sound in bypass
• The "Green Side" works perfectly
• Both LEDs work when the switch is pressed.

Things that don't work:

• Blue side doesn't work at all when that side is switched on, no sound at all.

I looked for a schematic for this one and it's not posted yet. I have attached pictures of the top and bottom.

Ryan

 

[Jazzwolf]

OK. Update!

Blue side is up and running and sounds great. Looks like that short was the killer. It now has good volume and the knobs are changing the sound as I would expect. Really good sounding Bluesbreaker.

Upon listening to the Green side again, it sounds great but the volume is super low. Like unusably low. The knobs work, but I cant get a useable volume out of the Green side.

I looked at the Green side schematic from the single pedal and it looks like there are some significant changes to how they laid it out on the dual board. This has slowed my troubleshooting. Is there a specific area I should look at that would explain my new issue?

Ryan

 

[Chuck D. Bones]

You found the short on the Blue channel thru visual inspection, right?

Inspect the Green channel until you find the short, open, wrong resistor, etc. There is no shortcut.

 

[Jazzwolf]

I have traced a majority of the circuit and so far have found nothing too crazy. The 43k R10 resistor is reading as 38k, would this be lowering my volume? When measuring voltages, what pins should I measure on the ICs? I hit pin 5 of IC2.2 and got 4.22volts. Still working on teh rest of teh circuit.

Thanks!

Ryan

 

[Jazzwolf]

OK. So the schematic from the single "Green" pedal seems to have significant changes from this dual pedal. This is making it hard for me to troubleshoot the issues. IC 1.2 is actually on the IC 2 and IC 2.2 is on IC1. From some of the reads I think there are some changes past the 1.2 chip on the schematic as after that I have had a hard time tracing it. I am currently doing a full visual band review on the resistors to see if they are matched the value printed on the board. This is my best hope of identifying an issue until the documentation is released for this build.

Thanks!

Ryan

 

[Jazzwolf]

OK. So the schematic from the single "Green" pedal seems to have significant changes from this dual pedal. This is making it hard for me to troubleshoot the issues. IC 1.2 is actually on the IC 2 and IC 2.2 is on IC1. From some of the reads I think there are some changes past the 1.2 chip on the schematic as after that I have had a hard time tracing it. I am currently doing a full visual band review on the resistors to see if they are matched the value printed on the board. This is my best hope of identifying an issue until the documentation is released for this build.

Thanks!

Ryan

Just got the full Pro-10 Dual schematic. This should help!

 

[Jazzwolf]

OK, I got this bad boy working! Between R127 and pin 5 of IC100.2 there was no connection. I made a solder bridge between them (since the connections were super close physically) and it came back to life. Not sure how that connection broke, wonder if it was a board defect?

Thanks for the guidance!

 

[Chuck D. Bones]

Looks great! Don't be too quick to blame the board mfgr.

 

[Jazzwolf]

Looks great! Don't be too quick to blame the board mfgr.

Oh, I am not blaming PedalPCB, just confused how that connection was severed. I just bought two more boards from them so I am not worried about their quality, again, just confused about my issue.

Thanks!

Ryan

 

[ntuncer]

Just a quick question, any idea how to reduce the bass of green side of Pro-10? Increasing R109?

 

[Jkhicks]

Those readings are close enough. Shorting pins 6 to 7 on the TL072 would kill the signal on the Blue side. It would not damage the opamp. When you get the socket out, you'll probably find a solder splash or a bit of conductive debris underneath.

I have the schematic and I gotta says that if this is an accurate trace, then the person who designed the Blue channel does not understand circuit design. Should it work as-designed? Yes. Does it contain a bunch of superfluous parts? Definitely. The Blue channel is a Blues Breaker with a 11.7dB boost at the end, hence the name. The Green channel is an ODR-1 with a slight reshaping of the bass response on the first stage. In case you were wondering, Nobels paints the ODR-1 green.

What if you have everything working,but the green side volume is very low? With the volume pot all the way up,it’s the same volume as the amp. No boost to the signal. I have 3 of these with the same problem. Thanks