Session 500 reverb feedback

Anders Brundell · Post by **Anders Brundell** » 14 Jul 2003 10:22 am

The spring reverb in my Session 500 has a tendency to feedback (or "sing" for me in a strange way) even at zero input signal, all of a sudden, and I can´t figure out why, or what to do. I have a dim feeling I had that problem many years ago, but I can´t remember what I did to fix it. It doesn´t seem to react on pre or post gain levels either.
Any suggestions?

Graham Bland · Post by **Graham Bland** » 15 Jul 2003 9:07 pm

Anders,

I used to have the same trouble when I first got mine. I found out there is a sympathetic
vibration between the reverb pan and the cabinet.

The answer for me was to take a piece of foam
and float the pan so it won't touch the cabinet in any way on the inside.
This will solve your problem

Anders Brundell · Post by **Anders Brundell** » 16 Jul 2003 12:28 am

Thanks, Graham!
I´ll try that and see what happens.

Anders

Brad Sarno · Post by **Brad Sarno** » 16 Jul 2003 6:45 am

You can try to insulate the tank from vibration but that may not fix it. Sometimes old reverb tank springs just get prone to resonating or feeding back at a particular frequency. I had to replace my Nashville 400 tank and the problem went away. The new tank didn't need any foam or anything, it just sat in the bag which was screwed down like normal.

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Brad Sarno
Blue Jade Audio Mastering
St. Louis

Anders Brundell · Post by **Anders Brundell** » 16 Jul 2003 8:43 am

Actually I´ve cheated - I´ve turned off the spring reverb and use a stomp box instead. It sounds even better, BTW. Call it being lazy, save energy or whatever, but I actually prefer to practice for upcoming gigs right for the moment instead of using screw driver and 4 letter words to fix a very analogue reverb unit.
I´ll fix it by and by, however, so thanks for all hints!

Kenny Dail · Post by **Kenny Dail** » 16 Jul 2003 12:44 pm

Turn your amp on its side. In other words, the reverb tank will be verticle instead of horizontal.

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kd...and the beat goes on...

[This message was edited by Kenny Dail on 16 July 2003 at 01:46 PM.]

Anders Brundell · Post by **Anders Brundell** » 16 Jul 2003 11:35 pm

Simple and well functioning soloutions are typical for a genious mind. However, there´s a nuthouse not far from here, så I don´t think I dare to try, but I´ll keep it in mind. (Maybe I can monut the reverb unit hanging on the amp side, BTW.)

Wiz Feinberg · Post by **Wiz Feinberg** » 21 Jul 2003 4:37 am

I have had feedback problems with most can reverb units and solved them all by sticking 1/2" thick, black automotive door foam on top of the unit, in different lengths, until the resonance stops. This is the stuff that comes in rolls and has sticky tape on one side, and is about 3/4" wide.[This message was edited by Wiz Feinberg on 21 July 2003 at 05:38 AM.]

Anders Brundell · Post by **Anders Brundell** » 21 Jul 2003 8:35 am

I´ll try something similar, Wiz.
I have some engine room foam plastic left over after sound insulating a boat engine hood, and I´ll try that. It´s a lot thicker than just ordinary foam plastic.

Bob Metzger · Post by **Bob Metzger** » 21 Jul 2003 11:40 am

The definitive test, if the wires length allows, is to run the amp with the reverb pan connected but placed outside of the cabinet. If the feedback stops, then it's the mechanical coupling of the pan and the amp/cab and the above suggestions will remedy your problem. If the feedback continues, try dampening or replacing the pan.

Bob M.[This message was edited by Bob Metzger on 21 July 2003 at 12:41 PM.][This message was edited by Bob Metzger on 23 July 2003 at 12:08 PM.]

Mike Brown · Post by **Mike Brown** » 22 Jul 2003 11:29 am

I think that this problem has been solved. It sounds as if the springs in this 15 year old amp are sagging and sensitive. I suggest that you replace the reverb pan.

Mike Brown
Peavey Electronics Corporation

Anders Brundell · Post by **Anders Brundell** » 22 Jul 2003 12:26 pm

Eh,... no, Mike! Actually the springs are just like a teenage boy´s **** after brought back in place again. One of the 2 reverb springs had slipped off one hold hook and laid at the pan bottom. At first I thought that a piece of thick foam plastic under the pan had made it, but the feedback returned after a short while. Now I´ve hooked the spring back in place and padded with some extra thick foam plastic, so now I hope it´ll keep in place for another 10 years or so.
I´ve test played it at all thinkable volume levels at full reverb, and everyting sounds just fine, except that my otherwize patient and sweet whife threatened to kick both me and the amp out of town.
This reverb has a character of it´s own, that no stomp box can produce; that´s why I want to keep it.
Thanks a lot for all hints, everybody!
It´s amazing how many nice and helpful fellow pickers there are at this Forum!