marnin, yawl (that's mississippi for hello)
finishing up my first custom circuit build (cathode bias, class A with 5881 and toggle to activate 2nd 5881 in case of emergency, has full assortment of treble bass mid controls [5f8-a tone stack] all in a tweed vibrolux box w/ alnico 10, 20 watt OT). She's passing a nice full signal but with what sounds like a 60 Hz hum in the power tube section.
I grounded all of the following to a single point:
1. filter caps
2. red/yellow PT center tap
3. power tube cathode bias assembly (this is the one I currently suspect as needing to be separated given its proximity to signal... does this sound
like something I should ground to another location?)
I double checked my heater pairs, they hit the same pin #s on both 5881s and the same ones on the 2 ax/ay7s (I don't recall if they are supposed to alternate for example pins 4/5 on v1 go to pin 9 on v2 or if pin 4/5 on v1 should go to pin 4/5 on v2 etc)
I don't have a choke installed.
The heater has a center tap (green yellow) that I soldered to the inside wall of the chassis with my 80 watt solder canon.
Got to nail down that blasted hum!!