MGSchindel

Also, all the 1987 Silver Jubilee heads (the 50w, the 100w and the 50w short chassis), as well as its 1988-1989 successor, the Marshall "Custom" in Black tolex/gold face plate, and then later the Slash 2555 reissue signature model, all have a clipping diode circuit in the preamp, that you can either engage or disengage via a pull-switch on the preamp gain knob. ON that amp you can hear for yourself what the clipping diodes do to the tone the minute you turn them on...SUCK THE TONE DRY, CUT DOWN THE VOLUME, HACK THE BASS, MAKES IT THIN AND SCRATCHY, AND KILLS THE NATURAL TUBE WARMTH AND PUNCH, for just a little extra "weed wacker filler scratch." Say no to clipping diode distortion on a marshall preamp circuit!

And the 4100/4500 JCM900 Dual Reverb, BTW actually has like three op amp chips soldered on the pc board, like a Boss DS-1 distortion pedal in a marshall headbox....NOT just a simple series of clipping diodes in a row to make a hotter crunchier tube gain signal...Go look at the schematics in the back of the Doyle book and see for yourself. It's those little triangles with a circle thru them on the preamp circuit schematic. That's why its cleans are so pristine and its gain is so...meh! The effects loop on the JCM900 with those little recessed trim pots is solid state buffered rather than tube buffered also, so when you use its effects loop, you're running your whole signal thru the solid state signal stages...not a pure tube signal path at all.

I'm not saying good or bad, it's just fact. The 4100 is great for cleans especially! Then again, so is a totally solid state Roland JC120 2x12 combo!!!! Killer amp.

Also the JCM800 2205/2210 has not just clipping diodes but a whole IC chip on the board to add to its gain. You can see it on the schematic, or open the head and it's blatant. A big black rectangular solid state chip soldered on the board, kinda like the chip inside a boss SD-1 or a tubescreamer pedal.

Then again, most guys that run an all-tube 2203 or 2204 run a Boss SD-1, Ibanez TS-9, or some other solid state overdrive pedal into the preamp input, to create enough distortion to crunch, thrash and shred on it anyway, so....