Transistor (Maybe?) problem

[Gregory Kollins]

I recently build an OLC big cheese clone. I love the sound, like a big muff throwing up on itself and simultaneously crapping it's pants. It's fantastic. But It's started to develop a few odd symptoms.

When I plug it up, it works, and will continue to work for 5-10 minutes, but after a while it will cut out and start making a LOW volume, blatty, gated sound.

Another symptom: it has always, and possibly coincidentally, cut out when I hit a chord or note really hard, like abuse the strings with the pick kind of deal.

Last symptom: If I unplug the adapter, then immediately plug it back in, it'll start working again.

So, the blatty gatted low volume sound makes me think, transistors!". But the other stuff eludes my still infantile comprehension of circuitry. Help?

[dxm1]

I recently build an OLC big cheese clone. I love the sound, like a big muff throwing up on itself and simultaneously crapping it's pants. It's fantastic. But It's started to develop a few odd symptoms.

This sounds suspiciously like another oscillation problem. Has there been a  epidemic of these lately?

When I plug it up, it works, and will continue to work for 5-10 minutes, but after a while it will cut out and start making a LOW volume, blatty, gated sound.

If your circuit is on the bleeding edge of stability, it may start off operating correctly, teetering on the edge of run away oscillation.  All it needs is a push in the right   (or wrong...) direction.  Either a 'magic frequency', or an input level that causes it to trip over into never-never land.

Another symptom: it has always, and possibly coincidentally, cut out when I hit a chord or note really hard, like abuse the strings with the pick kind of deal.

That would be an input level trigger.  Unfortunately audio circuits seem to oscillate in the inaudible frequency range (why is this?) - either very low or very high frequencies.  The circuit spends so much energy amplifying these frequencies, you hear a distorted, low volume signal in the audible range. Do you have pets? Dogs quickly leaving the area are a sure troubleshooting sign that you have a high frequency oscillation problem.

Last symptom: If I unplug the adapter, then immediately plug it back in, it'll start working again.

By removing the power, you are resetting the circuit to the 'teetering edge' stage again, waiting for the next trigger event. The Microsoft Solution.

So, the blatty gatted low volume sound makes me think, transistors!". But the other stuff eludes my still infantile comprehension of circuitry. Help?

Maybe, but more likely a wiring or layout issue. How is the off-board wiring?  Are there any high gain signals going and returning to the board?  I have a scope, and it makes finding the source of oscillations (usually) pretty easy.  If you don't have one, someone more knowledgeable about troubleshooting oscillation problems without a scope will have to chime in...

[Paul Perry (Frostwave)]

When a circuit consistently "gradually dies in the arse" like this, it's usually either a battery, or an electrolytic cap, or something overheating.
You have eliminated the battery - my money is on a dodgy electrolytic.

[Gus]

http://olcircuits.com/

Ask them

Years ago I traced and shared the Cheese Source schematics.  Then R.G. did the GC.  Now someone is selling kits?  I did not feel bad about the tracing of the schematics because I did not think people would sell kits I was thinking more DIY.

Good luck getting it fixed what not ask OLC for help? they are making money.

Who is OLC and were is the support forum

[snap]

http://www.diystompboxes.com/smfforum/index.php?topic=64368.0

[Gregory Kollins]

Thanks for the tips. I will talk to the OLC people and see what they think, in the meantime I'll examine my wiring, and maybe plug it in and see if anything gets hot... This is not my first project, but I just started doing this like a month or so ago so... my wiring could easily be an issue.

Oh, and a little thing that may be a big thing: I ran out of 24 gauge wire, so 2 connections are made with 22 gauge. would this be a problem...?

[snap]

Oh, and a little thing that may be a big thing: I ran out of 24 gauge wire, so 2 connections are made with 22 gauge. would this be a problem...?

No.