loud hum in Carte Palomino V16

[Bluefinger]

Hi,

I habe a Palomino V16 (2xEL84 amp) here that has a loud hum. WIth the master volume off, the hum is gone and it gets louder, the more I turn it up. The gain control has an effect on it as well but not as much. Th hum is a G#1 which means it's around 50 Hz. I'm in Europe where we have 230V/50Hz mains power so I guess this means that I have a dead filter cap, right? Any other obvious reasons for this?

Tubes are good btw, they have been changed reicently but the hum was there before and after the tube change.

thanks!

[pdf64]

50Hz can't be from the B+, as the frequency of the rectified wave is twice the input, ie 100Hz.
Unless you've got one of Alan's cast off PTs with an unbalanced B+ winding!
But most would be hard pressed to tell 50 Hz from 100 Hz, myself included.
So yes, if definitely not a tube (sub in known good ones to eliminate) then maybe a bad B+ cap, poor ground return connection etc.

If really 50 Hz, then check the heater circuit ground reference is good and again, eliminate it being a bad tube.
Interference from the heaters is usually quite a buzzy sound, rather than hum.
Pete

[g1]

If the master kills the hum, it is unlikely to be a filter cap, and can only be a filter for stages before the master.

[Bluefinger]

Thanks a lot! I'll replace the filter caps and check ground connections ...