Quote:
Originally Posted by Valvepower
Just a quick thought, but could there be charging pulses and power supply filter noise etc. from the axial reservoir and filter capacitors being fed into an unfavourable point on the ground?
Can’t make out where the reservoir and filter capacitors are actually grounded, but on the 5-10 I have in the workshop they are returned more or less to the CT and OV mains transformer end of the ground buss so as to keep the pulses and noise close to the transformer CT and OV point?
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Hi Terry,
I think you're right, the caps are grounded on the nearest valve base, which is the EF86.
So that means the high gain pentode stage has pulses across it? When I pull the EF86 out it kills the hum.