Perhaps because the speaker wires were acting as a counterpoise, and
actually increasing the conducted emissions on the power leads. Did you
try a common mode filter on the power leads when the speaker leads were
connected?
73,
Scott K9MA
On 10/5/2020 1:00 PM, Hare, Ed W1RFI wrote:
< Second, every wire/cable connected to a noise source (in this case, the Class D
amplifier, but also including switch-mode power supplies) forms a transmitting
antenna for common mode current on those wires. So nothing in your lab tests is
surprising.>
Actually, it is very surprising, at least to me, because when we changed the
nature of the speaker loads, the conducted emissions on the AC mains increased.
--
Scott K9MA
k9ma@sdellington.us
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