I'm having a problem with my quadrovibe build. It distorts when I have my guitar's volume turned all the way up, but is clean when I roll the guitar volume back to about half way. The effect works as it should other than this problem. I have the same issue if I keep the guitar volume at halfway but have another pedal that adds gain in front of the quadrovibe. It seems the input is overloading the circuit somewhere. The distortion is the same no matter where I set the vol, intensity, or speed controls. I assumed maybe I had the gain trim set too high, but it seems to do it no matter where the gain trim is set, so it must be happening earlier in the circuit. I was thinking maybe I should try another j201 for q1? I know they can vary quite a bit. Any help would be appreciated. Thanks.
Definately sounds like an issue. I would start with checking the values of the parts in the input section, but it could really be a mix up anywhere in that circuit. It's easy to put a 100R instead of a 100K in, or switch a 1K and 1M resistor when you're populating.
Jacob
Thanks for your help. I'm in the middle of double checking everything now. Hopefully it's just a incorrect resistor value somewhere.
Post your voltages, too. :)
this circuit should have very low gain (a hair over 1x) when in vibe mode. Tremolo mode does have more gain, due to the trimmer.