-i tried one, then immediately bought one, when they were new & just released, gave it the typical Marshall treatment that a life long Marshall dude does,
-VARIAC-a Marshall with out a VARIAC is like a Rottweiler that's been neutered-(WTF)-makes zero sense.
-biased that bitch as hot as the trim pots would allow,
-put the best NOS/ASNOS & used,.. PRE-AMP glass I had in my top secret tube stash in, did the roll & poll,
-GOLD LION KT88's-(NO$ 88's!!!, -ouche babe- the KT88 testing was expensive, and of course the mo$t expensive 88's won.
-SPEAKERS-well, it is a Marshall, start with GREENBACKS-then add the missing ingredients-(the big iron, with high plate voltage make the 2203KK unique, Thou the DNA, circuit design & unmistakeable-MARSHALL-MID-HONK- makes sure it will never be confused as anything but a Marshall, a welcome surprise, IT SOUNDS "UGE"!!
-Home work & testing- what bias & at what voltage sounds the best, and whats needed to take advantage of the KK's bias & voltage sweet-spot.
-Modded the bias circuit with new resistor & trim pot for more sweep & higher bias-(voltage 85, bias set HIGH!!-( i set bias by ear, if your bias is in the tube manufacturer's spec. sheet's safe zone, for that specific tube, lock and load!!