Some time ago, I bought a mid-1970s Marshall that had been modified by Peter Diezel. It's a ... 'significant' ... mod: It looks like two extra preamp valves, but there's also a third one just behind the blue cap. It went 'pop' a few months ago and I put it on one side to dig into when I have more time on my hands. Well, business always slows down in Summer, so in preparation, I got it off the shelf to take a look-see: Three new valves with 3D point-to-point components directly on the sockets. This might be a bigger job than I expected. :-o I wonder if Peter kept a schematic...? It does (did!) sound glorious, but I can see why he switched to PCBs for his own high gain amps. Wish me luck.