Noisy 9V Batteries?! & An odd issue with an RCA 5T Radio

[vortalexfan]

Originally Posted by old_tv_nut

This voltage variation sounds like it's a trivial change in the waveform, which the meter picks up, not a change in the fundamental power.

Do any other radios behave the same way?

This is the only AC Powered Tube Set I have that has AVC on it that is currently functioning properly so I have no way of knowing if any other sets I have behave the same way or not. I have a 1970s vintage GE Hi-Fi AM/FM Clock Radio that for some reason when I listen to AM on it, is unaffected by the occasional oddball AC line noise for some reason, the only noises that affect it is Lightning noise and bad computer power supplies.

I have a mostly functioning Zenith J733 AM/FM Clock Radio from 1952 that does some bizzare stuff every once in a while, but it doesn't have AVC built in, which might be part of the reason why it functions/acts the way it does.

Like I said my Coronado farm radio does some funky stuff but its only affected by "radiated" RF noise rather than AC Line noise since its a battery set.

I also have a 1967 vintage Magnavox AM/FM/FM AFC dual speaker radio that also seems to be affected by oddball AC Line Noise and that set was completely recapped (also it was supposed to have one of those line coupled FM antennas but it was missing so i had to juryrig one up for it but it doesn't seem to work quite right still.

Other than those issues I really don't have much trouble with my radios.