jwb wrote:
getting an ac hum problem on my heathkit hr-10 receiver.
which filter caps would i replace?

All of them. All of them.

or can it be a tube?

Sure, but if it's in the both the audio section AND the RF section, it
is probably B+ filtering.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."