Alessandro Deluxe Reverb Reissue Parasitic Oscillation?

[Stevem]

I have no problem with that!

[fenderbender]

Structo suggested replacing the Reverb driver tube. I think that would be a great place to start. You said that the power tubes had never been replaced, I'm willing to bet that the preamp tubes haven't been replaced either. I lost track of, a long time ago, how many times replacing a seemingly ok pre tube with a different one, fixed a noise issue (hum included).
Also, I've worked on Dr.Z amps, where the Reverb tranny was wired in backwards. With this, I mean That: the Blue plate lead went to B+ and the Red wire to the plate, The Green 8 ohm secondary to ground and the Black to the reverb tank. My Boogie MkIV was wired the same way. I'm guessing, possibly to cut down on oscillation.
Also, The Reverb input could be to close to the speaker magnet, move the Reverb pan bag around and see if it makes a difference.
All that being said, I would play with the reverb pan placement and get a new reverb driver tube and take it from there.
Good luck!
Tom

[rooster]

Toss the Accutronics. It's not causing your added noise but, based on trad reverb sound, the MOD tank is the only one to buy these days.

[Firestorm]

Toss the Accutronics. It's not causing your added noise but, based on trad reverb sound, the MOD tank is the only one to buy these days.

Aren't they all the same now? Beltron Korea? Years ago I bought one of each and tested. Nothing definitive. But construction style of each was identical. Subtle differences in termination, but otherwise the same. Happy to be proven wrong.

[pdf64]

Some info regarding the current tank offerings here, along with lots of other reverb tank stuff https://www.amplifiedparts.com/tech_cor ... d_compared

[rooster]

pdf64, that is a good reference! I did not know that CE owned MOD, hm.

Anyway, I have tracked down the early Gibbs tanks (two springs #3 delay) and the MOD can get very close. Not exact, but the best of all the repros IMO.