[Hammarlund] Fw: Hq170 hum

[Lee Bahr]

When audio engineers designed tube type audio amps, they twisted the
filament leads together going to each tube and ran the leads from the
transformer to each tube socket.  they did not use ground as one of the
leads.  They also used a hum pot to balance the hum out. They also used
science to determine where to run wiring and separate out the audio lines
from filament lines.  They also used shielded cable.

I think by making your radio have greater fidelity you are opening a can of
worms and now expecting the present design to accommodate your new audio
bandwidth.  The designers did not take into account what you have now
demanded from their design.  Their design did not pass 120 cycles and you
made it do so.  This may be a bigger project then you expected.
Lee Bahr, w0vt