A Cleaner Clean Channel

[printer2]

I would like to explore the schematic more but I have other projects calling my name. I did take a brief look at the schematic and scratched my head on IC M5201. It has two inputs and one output. Almost seems like an instrumentation amplifier so I googled those two words with M5201 and out came this. Well look at that, have never seen one of these before.

http://www.audiolabga.com/pdf/M5201.pdf

As far as the clipping diodes after the clean channel master, I am guessing they wanted the clipping done here rather than have the power amp IC clip with the loss of NFB. Something I want to do with an amp I will be building.

[J M Fahey]

M5201 is a *switching* Op Amp, meaning 2 op amps in a single case, each has its own inputs of course, there are also two outputs, but only one of them is connected to the pin labelled output at any time.
They so have a free unused pin, which they assign to the voltage controlled switch.

The Op Amps themselves are basically same as in TL072

As of clipping diodes even in the Clean labelled channel .... hey !!!!! ..... itīs a Marshall!!!!!
What else did you expect?