Well I found that out with the Silver Mica Capacitors. The ones I removed from the amp were cheap non branded ones I bought off ebay from Jellyfish Audio. I believe they are Japanese as I've seen them listed coming from Hong Kong. When I replaced them there was such a big difference it was like changing all 3 pre amp valves! Unbelievable. Cheap parts never again.
As for the wire I embarrassingly went by the photo which showed nice thick solid core wire. However if I actually looked at the measurement I would of known how thin it was. Its almost like telephone wiring! Hoping to get thicker stuff from RJ later in the month and will then rewire the amp. It has to look the part as well as sound good!
the high end of the audible spectrum has a huge influence on the tone we percieve it seems.
In a superlead the ceramic 250pF seems a lot more aggressive than SM to my ears. Mine was factory built with two 500pF in series. I have yet to find anything that snarls like it.
"Man, if you think changing all the caps makes a difference you should try swapping the circuit out to my magic Marshall specs and stop messing with your amp for good."
I've got a JTM1 that I built which uses 2 of those cheap silver micas and it has never sounded great. I've only got 1 of the good silver micas left so i'll change 1 and will see how it sounds. Tried looking for a 500pf ceramic on ebay but couldnt find any.