Hmm pedals.. pedals for thrash eh?
I've used Boss DS1, MT2, Mesa VTwin pre, Marshall Guv'nor and a zoom 505 multi fx, all into the clean channel on me Marshall VS65r and managed to get a good late 80s thrash sound. The MT2 I love, as I've gotten Tool, Sepultura and rockabilly sounds out of it (I kid you not) and its not Keeley modded.
Keeley are great, but they tend to vintage/smooth the harmonics on those pedals. Its dead nice on the overdrives, the boosts and the blues pedals, but tbh I dont like what they've done to the distortion fx. :?
Its a contentious subject and everyone has a different view. :lol:
With reference to the Valve King, I've seen a coupla bands on the Guitarist forums who've gotten hold of them and absolutely loved them. One is a death metal kind of band. Now the one thing I will say about this amp is that demand is VERY high and it can be quite hard to get your hands on one to try out. Some are also questioning the fact that its made in china, though I dont know why, as everything is made there thesedays. :lol: