Odd noise in left channel

[vetmed]

A sort of irregular "rustling" noise, kind of like the sound you hear on a microphone in windy conditions. Not loud, is drowned out by music playing even at moderate levels. Mine are 2A3 versions with later updates. Other channel sounds very quiet. Opinions, educated guesses gratefully accepted.

[fullheadofnothing]

Swap tubes and see if it moves.

[vetmed]

Yes, you were right. Was not really expecting that since these are not very old and have not seen a lot of use I replaced with an older tube that worked just fine. I assume that such noise is not good, but any idea what is happening? Thanks

[Paul Birkeland]

It could be as simple as a dirty contact on one of the tube pins.