I have hum while in standby (100 watt Marshall head) and I'm thinking it's the PT inducing hum into the OT and I'm waisting my time trying to reduce it?
1. Ground is good and tested amp at a different location across town, no effect on hum.
2. Volume has no effect on hum.
3. Pulled all preamp and power tubes, still hums, no effect
4. Disconnected OT primary so there's no signal in, the hum would now have to be induced into the OT secondary via wires or PT<>OT induced.
5. Just for good measure I disconnected PT bias and HT supplies so at the moment there is only 120vac into the PT and 6.3vac PT out to the heaters. Still hums same as before.
The hum is not terribly loud, a 1 on a scale of 1 to 10 but not hard to hear a few feet away.
1. Ground is good and tested amp at a different location across town, no effect on hum.
2. Volume has no effect on hum.
3. Pulled all preamp and power tubes, still hums, no effect
4. Disconnected OT primary so there's no signal in, the hum would now have to be induced into the OT secondary via wires or PT<>OT induced.
5. Just for good measure I disconnected PT bias and HT supplies so at the moment there is only 120vac into the PT and 6.3vac PT out to the heaters. Still hums same as before.
The hum is not terribly loud, a 1 on a scale of 1 to 10 but not hard to hear a few feet away.
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