Build Your Own Clone Message Board

Would you be able to help me identify the first place in the circuit the wah effect should be audible? I am curious to test the signal there to see if the distortion is present. Testing various places in the circuit I can see the clean signal is always clean but any place I am checking for wah, the distortion is present. Thanks.

You should notice from the schematic that the 13600 is a dual chip, meaning it's two OTAs on a single chip. There are two envelope filter or wah stages. You should hear the first wah effect at pin 5. It then goes back into pin 7 and out pin 8 which are just buffers. Pin 8 is your ultimate output. From here it goes to the out jack. But it also splits and goes to a second wah stage. The output of the second stage is pin 9. The output of this stage feeds back into the input of the first stage. It also goes to the ultimate output, but the amount of signal from this second stage is controlled by the range pot.

So because the output of the second stage feeds back into the input of the first stage, you can never track down the distortion.

If you pull R16, you would be able to test the wah signal path in a linear fashion. Can you see from the schematic how removing R16 would disconnect the output of the second stage from the feedback loop and the ultimate output?

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

Thanks. I pulled R16. One thing I noticed in the smaller IC that pin 5 is clean but pin 6 is highly distorted. R19 and R22 are also distorted. I'm still learning how to understand schematics so I don't know what this really means yet. Does it make any sense?

That's to be expected.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

I see, thanks. Just curious, assuming you have seen this distortion issue before, what are common causes? Any specific areas of the circuit you think I should signal test next?
I’m already on my next build and using everything I learned from this one. Writing this one off as a learning experience but still curious to understand the possible cause of distortion.

I've never heard of this problem. If I'm being honest, I think the problem has to do with the quality of the build. You had a lot of issues from the beginning, and they seemed to only get worse. You've replaced the components that were suspicious. Your voltages seem okay. If you're absolutely certain that the problem isn't a bad solder joint or faulty wiring, I'm not sure what else it could be.

We're more than happy to keep at it if you are though. I'd probably suggest going back to the beginning and starting with new pics to see what we're dealing with now.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

For sure it is user error/build quality.

I just finished the spring reverb pedal and it went perfectly. When I started the wah pedal, it was my first time even holding a soldering iron! So I think I will just order a new kit and use everything I've learned from the forums and I am sure it will be uneventful.

Big thanks to duhvoodooman for putting up w/ my nonsense! My only fear now is building these is going to get addictive

Just to close this one out, ended up getting a new pcb and rebuilding. Everything sounds great now. Many thanks for all the help along the way.


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Thanks for all your patience. I'm really sorry we couldn't get the first one sorted out.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com