I recently got myself a Marshall Valvestate 8100 head, which sounds amazing for a hybrid amplifier. Now there is one problem with the amp, and that is that there is a low buzzing sound when I turn it on. It does not get louder when I turn up the volume or gain, and it doesn't disappear when I switch channels, which means that it can't be the pre amp tube that causes the problem. I don't use a grounded power socket, but my other amp (an Orange Tiny Terror) doesn't hum so I don't think there is a problem power wise. My guess is a bad soldering joint somewhere in the amp, but I have no idea where to start looking. Is there someone who can tell me how to get rid of the buzzing? And how do I identify a bad soldering joint?

Cheers, 
Brian

Hello

Picked up this combo a few weeks ago and its making some weird space age noises and im wondering if the valve needs replacement and if so what make i should be using.    Many thanks for your help 

I bought a Valvestate 8100 head with a AVT 4×12 cabinet but its lacking a serious amount of gain & sustain even on max. I changed the pre-amp tube but it didn't make a difference. It still sounds dull and weak. What could be the cause of it?

I've got a Valvestate S80 8240 which has developed a loud hum whether instrument plugged or not.

The hum disappears when it is tilted forward. Can anyone suggest a home fix?

I put up this question before but for some reason it seems to have been deleted!