Deluxe Reverb RI - Buzzin'!

[earache]

Hello All

Got a Deluxe Reverb Reissue that buzzes like an electric razor once the standby is switched to "play".

Swapped in known-good rectifier tube, power tubes and phase inverter tube - no change.

Retensioned the power tube and rectifier tube pins - no change.

Took out the long narrow board with all the pots and jacks on it. Resoldered all connections at the pots and jacks - no change.

Poked around inside with a chopstick with the amp live. Couldn't find any device that made the noise change.

No parts inside looked burnt. The caps inside the doghouse look ok, no bulging ends.


Any suggestions where to start?

Thanks In Advance! - earache

[The Dude]

Does the noise go away when you turn the volumes down? If it does not, I would check for ripple on the supply lines. You could have a bad filter cap. If it does, it could be something as simple as cracked solder on an input jack. Also, check and/or resolder the output tube sockets. These amps are notorious for having cold joints on the sockets.

[TimmyP1955]

Most of the bad caps I've encountered looked just fine, and some were not that old - just duff.

[pdf64]

Buzz can be heater related; what's the resistance between the heater line and the circuit 0V?
If ok it could also be a tube with bad insulation between heater and cathode; try swapping in a known good 12AX7 in V1,2,4 slots.

[earache]

Hello All - tested the filter caps and a couple of them were shorted. Replaced all of them and the problem has gone.

Thanks for your help as always, you guys are the best!