Tubes4ever wrote:peterh wrote:jsl1234 wrote:Does it make sense to swap power tube positions first?
no
that would involve rebiasing all of them.
But using the triode/UL switches might be an idea as the problem started at the
time they were used.
I had a very similar problem and swapping the power tubes fixed the issue. Probably was a socket connection issue, but the problem was resolved. Rebiasing will not have an effect on whether or not the noise issue exists.
Pin diameters in octal tubes vary widely, too, so what might be too loose in one socket could fit another just fine.