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Old 26th Mar 2020, 9:49 am   #22
cathoderay57
Nonode
 
Join Date: Oct 2017
Location: Bristol, UK.
Posts: 2,389
Default Re: Quad 11 test run

Hi Mike, I would recommend you stop running the amp with one or more valves removed. It really isn't going to help because the biasing of the valves is inter-dependent and you will be running the circuit in an off-balance condition. When all of the valves are in, do you still get a hum? Is there anything connected to the audio input? Cheers, Jerry
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