[Heathkit] GR-91 SWL Radio

[Charles Yahrling]

Just dusted off my old SWL listening radio, built when I was 12 yo.
Replaced the 4-way filter cap can with discrete electrolytics as
recommended but 60 cycle hum did not disappear as I had hoped.  In
fact, it's now more stacatto, but attenuates at top of volume range.
Mouser tech suggested tubes may  also be the culprit but I was
wondering if the rectifier diode could be the leaky.

Am I right in thinking the hum might be DC  ripple?

Any suggestions appreciated.

chuck