Power Frequency Ripple Reduction in B+ Supplies
There was no need to pay any special attention to 50Hz mains hum.
Patrick Turner.
Don't recall anyone here saying there is a problem with power frequency
hum in a guitar amp. Except perhaps by bad grounding.
That is unless someone is using an SET!! Perhaps
Cheers to all, John L Stewart
Hmm, I made a 55Watt SET amp in 2009 which has 2 x parallel 845 tubes which operate from B+ and B- rails, +/- 600Vdc. If ever there was a likelihood of hum, it was in these amps because the B- rail must be especially hum free.
The schematic is at my website.
When completed, the noise total at speaker output with inputs grounded was 0.25mV, without hum being dominant, and without much GNFB. I did use CLC filtered 10Vdc for the 845 cathodes.
SE amps can be very easily be made hum free but you got to get right away from the accountant driven features designed into nearly every crummy amp made since 1920.
Patrick Turner.
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