Ampeg SVT4 Pro noise coming through power section, but only present on FX Send jack
Is this possibly a tube issue?
A friend of mine called me over to help troubleshoot the nature of the problem he's having. It's making a noise through his speakers; sort of a the sound you heard when trying to use a phone outdoors on a windy day, not too "swooshy", but about that frequency or tone (not real hissy, not real bassy, just air blowing sounds).
It does it with nothing connected. Makes no difference when you do.
From the front panel, the only things that affect it are Master volume and Treble control.
I also unplugged from the cabs and went from the line outs to another combo amp. No noise.
I do get the noise when using the Effects Send as a line out jack to the combo amp.
Seems weird to me that I can find a combination that is quiet, while one is noisy.
It is out of warranty, and may have never had tubes changes.
Anyone experienced anything like this or offer other trouble shooting ideas?