DYNACOMP

[lynessmy]

I built a DYNACOMP with TONEPAD layout using can-type CA3080 ( i bent the pin to fit to DIP8 socket).
I had to touch the body of the can or Q1 pins before this circuit sound to me.
The sound is not a proper sound, it sound like bubble popping and decay with time.
After release my touch, no sound.

Where should i start my debugging?
What is the purpose of the trimmer? to what point i need to trim it to?

[jlullo]

the trimmer you should set by cranking the controls all the way up, and dialing in the noisiest point on the trim pot.  it's basically to set unity gain.

that sounds like a misbiased transistor or transistor problems...

can you go through the debugging thread?  there may be a cold solder or solder bridge around the transistor

[lynessmy]

Thanks...i will check this probaly tonight...

as for the trimmer, i only got sound in certain spot, very narrow range.
She is totally muted beyond that range.

[jlullo]

there is definitely an issue then.  check out your joints to see if some are a bit blobby, and post up your voltage readings.  i'm sure we will be able to figure it out