Amplifier problem....volume/signal loss.


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06-03-2006, 09:08 AM
My amp has been flucuaing in volume from normal to nothing lately. It will play fine for a bit then act up for a few minutes then go back to normal a bit, etc..... the tubes are brand new, cables are good, cabinet is fine, there is no obvious/visible damaged components on the PCB, all solder joints seem good, there is no obvious external leaking of the caps.
What I'm looking for is people who have experienced this problem and have gotten it fixed.....what did the problem turn out to be? or any other opinions.
I bought new tubes and had a tech bias the amp and put them in. this was about 2-3 months ago..... The problem has been there before and after the new tubes were put in so I'm leaning away from the tubes scenario. My first instinct is caps or transformers but I want to hear what others have experienced. Its more of a random flucuation rather then a steady cycle

06-03-2006, 09:27 AM
Are you sure it's your amp and not your guitar? Cause I had a similar prob. with my old guitar. The volume pot was broken, so every now and then the volume became low and then suddenly high again. This happened usually when the volume was at 10. Turning it a little down eliminated the problem.

06-03-2006, 02:07 PM
I tried a different guitar on the amp and the same problem was still there.......then I tried those two guitars on a different amplifier and there was no problems

06-05-2006, 06:49 PM
I know what it is. I had the smae problem:
The pot has been oxidating. You shoudl put some contact spray on it. A quick sulotion is to turn the knob back and forth quicly.

06-05-2006, 06:57 PM
Yea, maybe.......... but I already dropped it off with the amp tech at guitar center I always go to. I will pick it up on saturday. Hopefully he can solve the problem...

.......I think I have G.A.S. for a Univox amp

.....anyone else have experience with vintage univox amps?

06-10-2006, 07:50 PM
Well I got my amp back from the tech at guitar center today and he did the following:
-clean all sockets and pots
-resolder "broken" joints.

But the problem is still occuring and now I have to bring it back next week to leave it there for another week.

Does anybody have any other suggestions of what the problem can be?

06-10-2006, 07:54 PM
replace, dont clean the offending pot.
thats what i would do.

06-10-2006, 08:28 PM
I don't even think its a pot though...... I have a feeling its either a transformer or the interior of an electrolytic cap. I will have a loooong talk with Mr. Amp Tech next saturday.