[murf]

Hello again fellas,
Have an issue with my 12S568 Zenith that I just re-capped.
Radio plays well, but after a few minutes it develops a humm.
Increases with volume.
Not noticeable on strong stations, but is there on the weaker stations and in between stations.
Checked all tubes and looked for anything missed or loose under the chassis.
Things has some awesome sound, just need to get rid of the humm.
All 4 E-cap were changed by previous owner. Has 2 22'sx450 and 2 10'sx450. According to the schematic those 2 10's should be 16's.
Would this cause the hum?
Will swap them out, but just curious if this can cause the humming issue?
Take care,
murf