Hi All and Justin ?

I suggested Taking the? B- to ground… ??I just want to remind anyone peeking in ??that this is not generally a good idea, and can be/is a dangerous thing to do. My comment was based on? Justin’s ?AC plug polarization scheme, and his particular tests with the scope probe ground.

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Justin

I suggested Taking the? B- to ground since it seems that you have done the same with the scope,? but ?that is not really a good idea unless the B- is proven again not to be the AC hot line[a fireworks condition]. Even with that, it would be better [safer] to have some variable resistance ?and measure the voltage/current first.

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A simple way of doing that here is by taking an analog vom set at a nominal 100+ volt scale, and cranking the scale down to a nominal 1 volt as long as the reading ?is not off scale. the VOM should swamp any ?small capacitance and leakage. You can listen to the hum too.

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Now if indeed this grounding really ?kills the hum , something is very strange. ?Is B- really floating / insulated from the chassis other than the intended R and C

IMO it is best to find the quirky thing rather that trying to swamp it out .

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