10-27-2015, 11:38 PM
(10-27-2015, 08:43 PM)OZ4 Wrote: So that's new? Earlier you said that pulling any of the 24 tubes had no effect. Still humming.
I apologize I was quickly reading and am upset with the chassis and thought you wrote 27 tube, not 24. The hum stays with all of the 24's out of socket or any one of then out. It naturally leaves when the 27 is pulled and is gone when the 27 grid is grounded. Filtering the source of the grid bias for the 27 did not affect the hum.