RFI or Capacitor issue?


We have an Audion Silver Night MKII, and it powers up silently. After it warms up a bit, I periodically get some light hissing in the left speaker, with an occasional high frequency noise that will rise in pitch for about 2-3 seconds. When I swapped the speaker cables, it moved to the right speaker. I've tried different tubes, and there is no difference. I've swapped tubes L/R, and there is no difference. I've got an appointment to take the amp into the distributor and have his tech look at it. He thinks that a capacitor is the likely culprit. But I want to make sure that I'm bothering him with a legitimate problem. I've not heard RFI or EMF noise that I know of, and wonder if that whining electrical sound could be interference from my wife's computer downstairs, or something of the sort.
Thank you all for your help.
Howard
boa2
I just turned off the computer, and am still getting the same periodic whining noise. Also, I am getting a light popping sound around the same time that the whining noise occurs. It does not sound like bad tubes--I've heard many of those. Maybe a tube socket? Resistor? Capacitor? I just want to make sure I'm not having a tech look at the amp for no good reason.
Does the noise change channels when you switch input cables?

Does the noise change when you gently rock/rotate each tube?
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1) Do you mean when I cross the IC's Red to Black & vice versa? I have not done that yet.
2) I get a slight popping noise (like the one I described) if I gently rock the left channel 6922 tube. The rising electrical noise is intermittent.