Help with amp volume dropping out

MadAsAHatter

MadAsAHatter

Well-known member
I have a Crate Stealth 50 (combo I converted to a head) where a number of months ago the volume would randomly drop out. It doesn't go completely silent, but it is a noticeable volume drop. Sometimes it'd happen while playing then come back 10 or 15 seconds later. Other times It'd drop out and not come back until I turn it all off and let it sit for a while. I brought it to the tech back then and he wasn't able to find any issues. He said he checked over the electronics, played it for a while and all was fine.

I haven't had that issue come up since then until this morning. Went to strum a few notes before leaving for work and the volume drop was apparent from the moment I turned it on. Any ideas what might be causing this? I don't want to pay a tech to look at it again just for them to tell me they couldn't find a problem.
 
So far I repaired few tube devices with this problem. It could be anything. Once it was bad tube contact, in other case just defective tube. 1 case defective plate resistor, 1 case switching FET transistor, 1 case grid resistors. The easiest what you can do is to check tube sockets, move tubes a bit, or swap them.
 
Clean the effects loops jacks with Deoxit. I have fixed a couple of crate / ampeg amps just with that. Heat and corrosion. Actually clean all of the jacks/pots/switches/sockets while you are at it.

You could have a cold solder joint that is breaking contact at operating temperature. That's an easy fix... After you find it.
 
I had a Mesa Roadster with a similiar problem ...... it was the screen grid resistors .... they looked absolutely fine .... but when I tested them on the multimeter one of them was gonzo .... sometimes they hold their value till they get to hot and they start to fail ... that why you might have volume for a bit until you have to let the amp cool off and restart .... and just partial volume also points to one or two of them failing ...
 
Thanks! I'll give the tube sockets, jacks, pots a good clean and check out what I can. Ultimately I think I'll need to bring it to the tech.
 
It’s either a bad tube, dirty tube socket, or cold solder joints at a tube socket.
 
skullfxr said:
Clean the effects loops jacks with Deoxit. I have fixed a couple of crate / ampeg amps just with that. Heat and corrosion. Actually clean all of the jacks/pots/switches/sockets while you are at it.

You could have a cold solder joint that is breaking contact at operating temperature. That's an easy fix... After you find it.
Click to expand...

I think you sent me on the right path with the effects loop.
As a quick test I jumpered the loop with a short cable and no more volume issue. As soon as I took the cable out, back to the volume going in and out. Did that back and forth several times. Each time jumpered = played normal, No jumper = volume went in and out.
Gave the jacks a cleaning tested it. Played for a good 45 min to an hour and not one problem with the volume dropping out. Now I just need to go back around and give everything a good cleaning.

Thanks everyone for pointing me in the right direction. Saved me a trip to the tech.
 
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