Harsh, Ringy Reverb

Robert · Post by **Robert** » 13 Jun 2002 4:12 pm

Thanks again to those who helped me the other day with another amp problem. The problem du jour is this: the reverb on a 20-watt combo is ringing, and on top of it - the depth of effect is half of what it should be. I used to run it at 4 and it was pretty wet and 3D. Now - even at 6, it's lame - and you get the ring, to boot. The reverb pan was situated right up against one of the speaker frames - I backed it off of the speaker and re-screwed it to the floor of the cabinet. I re-tubed the reverb driver (12AT7) and also all of the pre-amp tubes (12AX7), mostly because I was unsure of which of them handled reverb recovery. Still - it's not happening the way it should. Any ideas? Thanks.

Rob Yale[This message was edited by Robert on 13 June 2002 at 08:02 PM.]

Jon Light (deceased) · Post by **Jon Light (deceased)** » 13 Jun 2002 4:24 pm

I don't know if this is a high probability kind of thing but it caught my attention in a previous discussion--check the springs in the tank and make sure they look right and aren't hung up, twisted, crossed.

Bob Metzger · Post by **Bob Metzger** » 13 Jun 2002 5:53 pm

Reverbs (pans/tanks) are touchy mechanical devices; Make sure that its not bolted too solidly to anything. That why they are in bags alot, with cardboard (preferably Pre-CBS) on the bottom - to mechanically de-couple them from their environment. If there is too solid a connection, they will tend to feedback. Some people (like Fender) put weather stripping on the top of the pan/tank as well. Try using the reverb with the tank outside of the amp and see if that helps. If so, then you can devise mounting methods that we'll be asking you about!

Bob M.

Mark Herrick · Post by **Mark Herrick** » 13 Jun 2002 7:14 pm

Pull the tank out of it's cover and see if one of the spring attachments to the transducer is broken. (It's just a very thin wire.)

I had a broken one once and had to replace the tank. That's about the only way to solve that problem.

More info here:
http://www.accutronicsreverb.com/ [This message was edited by Mark Herrick on 13 June 2002 at 08:21 PM.]

Robert · Post by **Robert** » 14 Jun 2002 6:41 am

"If the right won't don't get you, then the left one will . . . "

I had swapped one NOS 12AT7 for another - the GE for the Phillips. I think the GE was a bum tube. I put the Phillips back in there and I have no problems. Just the same, I had the reverb pan out to take a look - everything looked "in place", and yeah, the thing was sandwiched in corrugated cardboard. The 12AT7 is just for driving the 'verb in this amp, a 12AX7 handles the phase inverter . . . this answers a question from a related thread. BTW - the Flynn's in Evanston are great guys and will take back the errant tube, no problems. I understand that isn't the case with every shop . . . and thanks, again.

Rob Yale

[This message was edited by Robert on 14 June 2002 at 07:42 AM.][This message was edited by Robert on 14 June 2002 at 11:14 AM.]