What on earth have I done wrong?

[jjg]

Hi there, newbie question alert. Just completed my third circuit today - a compressor. Obviously done something wrong as it works well when my guitar volume is really low, but higher than 3 I am getting distortion as well as compression. Symptom number 2: after playing guitar through the circuit for ten minutes to test it, I swear I have a tingling in my left hand. Is there any way I could be sending current from the circuit into my guitar?! I had the circuit board hooked up to a breadboard with a 9V battery.

[R.G.]

Hi, welcome and congratulations for getting all the way to #3 before running into a wall. I didn't fare that well when I started.

Experience with literally tens of thousands of first timers (... er, third timers    ) has shown that it is very easy to miss the orientation of some component, get off a pin or two on counting which pin is which, or get the wrong wire into the wrong hole. Especially with breadboards, some of the holes don't make solid contact with whatever is plugged into them.

Unfortunately, that makes the answer to "what on earth have I done wrong?" be "almost anything". That's not a comment on you, just a statement about Mother Nature's sheer cussedness in demanding that 100% of all connections be correct.

Over time, we have developed a step by step way to answer questions like yours. There is a set of stickie messages at the top of the forum. One of them is titled "Debugging - what to do when it doesn't work". Give that a read. It will help, and will help us help you.

[Mark Hammer]

I certainly can't speak to the "tingling", but it is a common event for those who have built something using a "sidechain" that detects the signal envelope (e.g., noise gate, autowah, compressor, limiter) to report something they descibe as "distortion".  It's not distortion in the sense of clipping, but rather an artifact of imperfect envelope detection.

Nailing a perfect envelope follower is hard.  If it responds too fast, it responds to every little signal squiggle, inserting little jumps at a rate in the audio range (above 20hz).  So a gate may trigger at an ultra-rapid rate, or an autowah will sweep up and down at a fast rate, that sounds gurgly, like someone clearing their throat.  This mostly happens during the decay part of the note's lifespan, where mperfections in the string can create "beats" that modulate the gain cell, filter, or gate at fast speeds.

Of course, at the other extreme, if one designs the envelope follower to be less responsive, you tend not to get the little burbles, but the circuit misses stuff that it should have adjusted to and can take impractically long to "settle down".  The trick lies in getting the right balance of responding to, and ignoring, sudden changes in level.

I don't know that this is what you are hearing, but it happens often enough that itis worth considering as a possibility.

[jjg]

Thanks both so much for your helpful comments, I'll check out the debugging pages! It is a dynacomp circuit on perf board, and I used the breadboard for hooking up the power and input/output, before putting it into an enclosure. First time I've used an IC (ca3080) and there are quite a lot of components, so plenty of room for error!