Been there.Save yourself some grief and borrow or steal another pre amp,plug it in the system and if the hum disappears you will have identified or eliminated the pre amp as the source.
Help with hum
I have a hum coming through both speakers. It is independent of volume control and completely stops when the preamp is disconnected. Disconnecting source from preamp has no effect. I have tried switching cables and tubes from channel to channel but it keeps humming. I have tried all combinations of cheater plugs on both amps and on the preamp but with no improvement. Any advice regarding cause or diagnosis is appreciated. Preamp is Cary SLP-98 and amps are Manley Neoclassic 300b's.
Thanks in advance,
Dave
Thanks in advance,
Dave