I have an Ampeg VH140c combo. I know, quite an old amp possibly full of problems. While I play, the volume slowly starts to cut back until you can almost not hear it. I turn it up, and all of a sudden the volume is back full force and is now rather loud. Local music shop has suggested that the speaker brackets may be loose, but they have made mistakes with my gear before. Any suggestions before I leave my amp for them to fix something that may not be wrong?
Adding information, the amp has both reverb and chorus built in that can be turned off. The problem occurs with every mixture of these two effects. Also, the built in speakers can be unplugged if you want to use the amp as a head and has two additional outputs for speakers/cabs. I tried switching the speakers to the other available outputs and the problem was not fixed.
I'd try cleaning the volume pot you touch with contact cleaner and see if that resolves the issue. Maybe that pot is going bad or has a loose/broken solder joint?

No idea what a speaker bracket would do here unless the speaker wires themselves are coming loose but just touching the volume pot wouldn't affect that.
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If it twer mine, I'd start by replacing the pot.
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What cath said.
And find another music shop.

And I'm gonna quote something I posted in another thread here...

Quote by CodeMonk

Geez, I can't believe how often often I hear people come in here and repeat what their so called "amp techs' said to them, and just face palm at the stupidity of said "amp techs".
Where the fvck are these so called techs coming from?
Last edited by CodeMonk at Sep 23, 2015,
On my '77 Ampeg VT-40 I had to replace some capacitors in it, my amp was doing pretty well the same thing as yours.
..I was watching my death.
Could be pots, could be a heating problem, could be capacitors...too many "maybe" things to adequately troubleshoot remotely.

And your local music shop should die in a fire.
“Ignorance more frequently begets confidence than does knowledge.”
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I took it to another shop. They told me the volume pot was not the problem. Each channel has its own volume control, there is no master volume. The chances of them both having that problem at the same time and not having the problem at the same time is slim to none. They have narrowed it down to a loose connection or the amp overheating. The problem occurs after about 25 minutes of play, either channel. After leaving it for 4-5 hours, it plays fine for another 25-30 minutes.

Quote by Arby911
And your local music shop should die in a fire.

I agree entirely. My Vox has been with their technician all Summer. The only reason I'm not breaking down their doors to get it back is because they are loaning me a slightly better amp until mine is fixed. My Ampeg was with them for two weeks before I went in to take it home. They had not even sent it to their technician, and could not tell me when it would be sent. Every possible problem had been an entire guess. They hadn't even turned it on to hear what was wrong, just wrote down what I told them and attached it to the amp.
Quote by metalmingee
No idea what a speaker bracket would do here unless the speaker wires themselves are coming loose but just touching the volume pot wouldn't affect that.

Looking back, I didn't go into detail enough here. The volume was on 1, which is plenty loud for a 140 watt amp with gain 7 or 8. I had to turn the volume up to 5 to even hear the amp a little. Then after a few seconds of playing like that, the volume popped back on. I turned it back down and after a few seconds, the volume faded to nothing again. The volume coming back suddenly was loud enough that I don't want to try and reproduce the situation.