Selmer Zodiak Treble & Bass tremelo low hum

[axtek]

Got my old amp up and going yesterday. Was blowing fuses but had some new diodes replaced and it works fine now except for a very low humming from speaker which doesn't get any louder as you turn up the volume. I also noticed that one EL34 tube is not glowing as bright as the other 3. I deoxed the tube pin sockets as well as the tube pins themselves but it didn't help. Any thoughts, ideas?

[Chuck H]

Old power tubes and filter caps.?.

[pdf64]

Deoxit type cleaners can be lubricating or non lubricating, depending on the intended application. It's bad practice to use a lubricating cleaning agent around tube pins / sockets; the lubricating residue is unlikely to have sufficient insulating properties, also may attract dust and so lead to arcing when the amp gets cranked.
Regards the hum, try operating the amp without the phase splitter tube in place. If the hum is remains much the same, try checking the static dissipation of all the power tubes, as imbalanced currents in the output transformer primary can cause this.
Pete

[axtek]

Thank you,
I'll have that checked.
Steve