[mythtv-users] myth .23 - after upgrade, buzzing/hum on audio all the time

[mythtv at derdev.com]

JYA packages against Mythbuntu 9.10
mythfrontend 2:0.23.0+fixes24710-0ubuntu1
Hardware is ION ITX 

I hadn't run this specific FE for 2 weeks (or more).  It was working
nicely with speaker output passing through a mini plug to the TV.

After software (apt) upgrades from 0.22 to 0.23 (and at least one brownout
of household power) I now receive a consistent white-noise hum/buzz over
the speakers when the Myth box is the selected audio input.  Regular cable
on coax input to the same TV does not yield the buzzing/hum.  

(the sound itself is a constant low hum that I would equate to how
long-distance telephone lines used to have a quiet, low hum)

This has also interfered with the volume of the Myth audio signal, it's
weaker.

I checked alsa-mixer and the levels look right.  Hum stops on TV if I
unplug the mini- input from the TV, so I'm pretty convinced the issue is in
the signal from the Myth box.

What kind of bothers me is that the hum is persistent in mythbuntu even if
I shutdown Myth FE...  could be drivers, could be hardware...  I'd be
bummed out if my audio chip got semi-fried in the brownouts, but its
certainly possible.

Just hoping someone has a lead for me.  Thanks!