I do not think that either will reduce humming from a resonant circuit with inductor and capacator. Humming is caused by a frequency mis-match and a resistor has to be added to dampen the oscillations. The varnish is only meant to insulate the inductor, be it a 700HP motor or a three micro-henry...
I am searching for an easy solution for an exasperating nuisance.
There is a public address system at work and before the start of the messaage a loud audio annunciator frequency has been added to warn people of the upcoming message and I want to locally supress it but still receive the...