Thanks Elliott!

My passenger was also experiencing the same symptoms I was, while his
headsets were plugged into the intercom system. First, he heard the
same scratchiness as the radio started to fail, then silence. He also
didn't hear my transmissions, when I lost side-tone and never heard any
transmissions between ATC and other traffic while on the local ATC
frequency.

That doesn't necessarily rule out a headset problem, but may make it a
less likely probability since we both seemed to experience the same
symptoms at the same time.

The connector, however, is suspect. Jim Weir had suggested I purchase
some connector cleaner spray, which I did and applied. That just
ensured the connectors were clean, but doesn't guarantee that the
connection is good. I will call the local avionics shop and see if
they can easily check a connector issue!

Thanks a bunch!
Todd