Ampeg reverb squealing

[danielzink]

Hey All,

so.........with my new dream amp comes a new set of issues.

First and foremost.....at 1/2 to 3/4 level on the reverb knob everything is fine...once the reverb knob is set to 10 a high pitch "ring" starts coming through...I have replaced the 6U10 with 2 others (that were supplied with the amp and seem to be new in boxes).

Any ideas ?

Thanks, Dan

[52 Bill]

...once the reverb knob is set to 10 a high pitch "ring" starts coming through...

Acoustic feedback? I just had a VT-40 in the shop for a check up, and it would feedback when the reverb was cranked to 10.

Try covering the tank with a towel to see if your problem is acoustic or not. If it is, try wrapping the tank in some foam rubber or tolex or bubble wrap, etc.

[Enzo]

Well Dan, since you have a couple thousand AMpegs, I am not sure which model we are speaking of. I am guessing this is not one I have seen?

Those triple triodes are all microphonic to some degree in my experience. Just because they are "new" in the box doesn't make them not microphonic.

Turn the amp up so it rings, and once it starts, reach back there and grasp each tube firmly one at a time to see if that stops the ring. if it does, that tube is microphonic.

REverb pans feed back too, but not usually at what we would call a high pitched tone. But to check, demount the pan and flop it outside the amp cab. if it is on the lower rear panel, just take the panel off and lay it down. ANy help?

While something else is possible, it is really most likely a tube or the pan.

If the tube, we could look for a sturdier tube, or we could dampen the one you have somehow. if the pan, Ampeg never bagged their pans, but you could. A strip of foam stripping along the top of the pan reduces resonance. I'd be happy to give you the material if you are in the area. I'll even apply if for you. If the pan is screwed down tight, that's bad. Move the screws over a little and leave them out a little so the pan can move.

[danielzink]

Thanks Enzo - I'll give it a shot.....

I figured when you read this post your eyes would roll back and you'd start twitching and lying on the floor crying

I just received the amp and other than this pretty simple issue - it works great.

I promise....no more Ampegs...really (same prominse I made to my wife BTW).

If I can't get it sorted - I'll drop her by sometime next week.


Thanks again !

Dan

Well Dan, since you have a couple thousand AMpegs, I am not sure which model we are speaking of. I am guessing this is not one I have seen?

Those triple triodes are all microphonic to some degree in my experience. Just because they are "new" in the box doesn't make them not microphonic.

Turn the amp up so it rings, and once it starts, reach back there and grasp each tube firmly one at a time to see if that stops the ring. if it does, that tube is microphonic.

REverb pans feed back too, but not usually at what we would call a high pitched tone. But to check, demount the pan and flop it outside the amp cab. if it is on the lower rear panel, just take the panel off and lay it down. ANy help?

While something else is possible, it is really most likely a tube or the pan.

If the tube, we could look for a sturdier tube, or we could dampen the one you have somehow. if the pan, Ampeg never bagged their pans, but you could. A strip of foam stripping along the top of the pan reduces resonance. I'd be happy to give you the material if you are in the area. I'll even apply if for you. If the pan is screwed down tight, that's bad. Move the screws over a little and leave them out a little so the pan can move.