Hi, with AC filament, which way would you use for grounding and reason (if any)?
1) ground one end of the filament.
2) connect each end of filament with a resistor to ground (virtual ground).
It seems to me either way does reduce hum, I just wonder which way is safer.
Thanks
1) ground one end of the filament.
2) connect each end of filament with a resistor to ground (virtual ground).
It seems to me either way does reduce hum, I just wonder which way is safer.
Thanks
Personally I prefer method #2 but using a potentiometer with Center leg grounded or DC floated with AC by-pass.... This way the the HUM can be nulled out better...
Never leave a heater circuit floating; it must have a DC reference. No electrode within a valve envelope should be left floating.
Grounding one side is simple and often sufficient.
Grounding a centre-tap (either via a CT secondary or a pair of resistors or a humdinger pot) can give less hum.
Both ways are 'safe' as there is no personal danger to be protected from.
Grounding one side is simple and often sufficient.
Grounding a centre-tap (either via a CT secondary or a pair of resistors or a humdinger pot) can give less hum.
Both ways are 'safe' as there is no personal danger to be protected from.
Also, try not to use the same wires or PCB trace for carrying heater/filaments and signal currents. Leave them to flow separately.
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