On 11/2/2017 8:25 PM, Clifford Heath wrote:
Also... as a filter in the power supply? Because yeah,
the one place you really want all that filtered-out
100Hz energy is in your speaker Or perhaps it was
arranged so that enough got through to the amp to
cancel it out? Crazy stuff anyhow.

Electro-dynamic speakers had the filed coil which
doubled as the power supply filter choke.
Alon with the voice coil, there was a hum-bucking coil
that canceled the residual hum from the field winding.

Several of the vintage radios I have, have electro-
dynamic speakers.


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Jeff-1.0
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