Amp cutting out

[Andrew Goulet]

Hi all, I don't know much about amplifier circuits or amps in general, but I have a problem with my Austin 400 cutting out. It seems to happen almost randomly. It will get very quiet or inaudible, and remain that way until I pick or strum really hard (sending a lot of signal) which makes the amp suddenly return to full volume.

Thumping the amp has also made the volume come back to normal.

I cleaned all connections with Deoxit to no avail.

If anyone more knowledgeable than I knows what it might be, I'd appreciate your thoughts.

[Donny Hinson]

It still could be one of the external jacks or controls (Deoxit won't fix everything), and it may also be some internal plug or jack, or even a bad solder joint. The only way to know for sure is to take it apart and poke around with a stick or plastic rod. (But I don't recommend that unless you know something about electronic circuitry.)

Time for a tech, probably.

[Jack Stoner]

Peavey's back in the era of the Austin used "flakey" molex connectors internally and for the reverb connection.

From your description of problem and apparently not an amp tech its time for a trip to a qualified repair center.

[Dennis Detweiler]

As Jack said. Every time I had that problem it was bad molex connections. I pulled each one, one at a time and cleaned them and/or used a tiny screwdriver to pry the female sockets slightly tighter. The only other connection problem I had was power intermittently dropping. In that case it was the 6 power transistors on the back of the amp that plugged into their individual sockets. I crimped those a little tighter and re-installed the transistors and all was fine.

[Jack Hanson]

I once had a similar issue with my LTD 400 and the problem turned out to be that the speaker wires were not making good contact to the connectors on the speaker itself. Easy fix.

[Tony Prior]

IF this amp has EFFECTS loop jacks, ( send/return) CLEAN THEM or put a 1/4 jack short wire from one to the other.

[David Michael Clark]

Austin 400 cutting out. It seems to happen almost randomly. It will get very quiet or inaudible, and remain that way until I pick or strum really hard (sending a lot of signal) which makes the amp suddenly return to full volume.

Thumping the amp has also made the volume come back to normal.

I cleaned all connections with Deoxit to no avail.

I agree with both of the Jacks above, and tend to find that generally a signal that fades out, drops off, and then returns once more gain ( more electricity or energy passing into the circuit ) or some gentle banging, can be a cold solder point, either on the board under the molex input jacks or to the speaker itself, and as stated above same theory on the wires to the driver itself. ( not making a connection until there’s enough electricity to bridge the circuit..) it is usually an easy fix, unless it’s not.

Not knowing your skill or knowledge with amps, I wouldn’t go poking around in there unless you have a general understanding of amp and circuitry, you might find something that will shock you.!.

I’m a new forum member and thought I’d toss my two cents in and say hello.
Hello.

[Andrew Goulet]

Thank you, everyone, for your replies!

I've cleaned the jacks again, including rear jacks, and tightened the speaker connections. They were a little loose, but I couldn't reproduce the problem by jiggling them (sound cut out completely rather than just diminished volume). I'm thinking it's a connection on the board that is loose. I spoke with a local music shop that offered to diagnose the amp for very little time/money investment, so I'm going to bring it in to them.

I got this cat-clawed amp for $50 and a short drive, so I'm happy to spend some dough to get it checked out by someone who knows what they're doing. It's loud, clean, and my main gigging amp, so I need it to be reliable.