I have one of these and they are awesome amps and I don't use that phrase lightly .
The 'clean' channel goes through a volume pot only then straight through the valves to the GH12 speaker , this really shows the true tone of your pickups , and can do chimney Vox style cleans , Just breaking up ' Classic Rolling Stones ' tones and much more .
The 'dirty' channel has 3 gain stages going from rocking break up , to insane overdrive .
All tones very musical ,takes pedals really well , enough volume to keep up with a furious drummer and a 1 hand lift into and out of the boot of your car!
They don't make this model anymore and they are already highly regarded and sought after , if you're in the market for a valve guitar amp , do yourself a favour and snap this up.