Fender Deluxe Reverb Reissue - Reverb Problem

[bw1985]

Hey all,

I've been working on a Fender Deluxe Reverb Reissue amp that I'm a little stumped on.

The amp sounds good and is functioning as it should except for one issue, when the Reverb control gets turned to around 7 or above and a note is played, the reverb makes a huge crashing sound that keeps resonating until I turn the control back down.

I've tested the tube and verified it is good, I've changed the pot to a brand new one and I've tested the tank and it checks out. Are there any other factors I could be missing here?

Thanks!

[nevetslab]

You could try injecting signal into the Reverb Return jack. It functions like an Auxiliary input to the amp NO EQ, apart from the Frequency weighting network applied for the tank. I've never tried to plug a guitar into that jack....but once you have an RCA adapter cable for that purpose, no reason why you couldn't. You could also try another 4AB3C1B reverb tank, if you're so fortunate to have one.

It almost sounds like acoustic feedback. Is the tank mounted in the vinyl isolation pouch? You could remove the reverb tank / pouch from the floor of the cabinet and place it away from the speaker, to see if that's the source. Iv'e certainly had reverb tanks howl on me when turned way up.

[TimmyP1955]

I once had a problem that was kinda similar. It turned out to be a cathode bypass cap (I cannot recall if it was in the drive or return). With the cap removed it was worse, with a new cap all was well.)

[Enzo]

Acoustic feedback in the pan? Move the pan outside the cabinet as far from the speaker as the cables allow. Any help?