intermittent problem on a deluxe reverb

[kaiomenos]

hallo
i'm having a little problem with a deluxe reverb from the 70s
well when the volume is set to 4 or higher on normal or vibrato channel i hear an unusual noise.
the noise ain't mechanical (speaker ,etc) it's probably electrical,thermal (it reminds me the noise of a broken pot)
it becomes alive when i hit a note or chord hard and dissapears a second or two after i stop playing.
any hints?
could it be arcing/spikes?
i have already installed 3 reverse biased diodes on each output tube plate but still goes on...

[Rick Erickson]

Check the solder connections on the 47 ohm resistor that runs lengthwise on the eyelet board, near the tone controls of the Vibrato Channel. It's very common to find this resistor loose. Beyond that - check every solder connection throughout the amp. Do not attempt to service your amp unless you are thoroughly familiar with the potential shock hazzards that you will be exposing yourself to.

RE

[Enzo]

Hah. I mentioned over at AMpage that you should post here and here you are already.

See my response over there. In addition to what Rick mentions, I suggested checking the main filters, checking the speaker itself, and checking for loose connections by whacking the amp.

[Don Symes]

checking the speaker itself

To expand on that a tad - try using a different amp tp drive this speaker, verifying that it's not a loose mounting nut or a rubbing coil.

Then, try plugging this amp into a different speaker cab to see if, when you stop shaking the chassis with the speaker, the noise is still there.

HTH!