Ver nasty problem with Quad

The problem occurs only on Lead 1

There's this 'nasty' sound under my tone, it's like a constant wish wash of white noise. It sounds pretty disgusting.

And then whenever Lead Drive or Treble is dialed up beyond 6 or 7, there is a shitload of squealing and peeping going on, the ugly sound I described in the previous paragraph is also still there.

Any ideas as to what this might be? A dodgy tube?

Maybe a tube went microphonic ?

"Microphonic tubes have something loose inside them that, when gently tapped or otherwise vibrated (like sound from your speakers) will cause the tube to make its own sympathetic sound. Just past marginal
microphonic failure you will hear a grumble when you play a bass note. More microphonic tubes wont let you turn up the treble without tearing out a shriek. Worse still you can't play lead style distortion without your amp squawking at you. There are lots of shades here, some grey. If you are hearing any tones that don't belong then you most likely have a microphonic tube. It may plague you only under certain conditions. But a bad tube is good opportunity to upgrade the sound of your amp."

+1 on above comment....

4Draw said:

The problem occurs only on Lead 1

There's this 'nasty' sound under my tone, it's like a constant wish wash of white noise. It sounds pretty disgusting.

And then whenever Lead Drive or Treble is dialed up beyond 6 or 7, there is a sh!t of squealing and peeping going on, the ugly sound I described in the previous paragraph is also still there.

Any ideas as to what this might be? A dodgy tube?

Click to expand...

It was lead2 dude.
It sounded very nasty, the strange thing is, it seemed to disappear when you are playing, but somehow it still was there.