it is worse on the clean channel than the overdrives. thinking now though that my guitar setup is part of the problem, i have twin humbucker pickups but i'm sure the neck pickup need adjusting.

Although it didn't sound as bad last night when I was using it without my computer on, usually it is on because I use the tabs in guitar pro.

Have ordered a new valve, for the sake of £9 as i'm not sure it's ever been replaced in it's 5 year, certainly not in the last couple of years by the lad who I bought it off.

Matt