I am working on a tube based guitar amplifier, and found an interesting schematic online. There is an op-amp that has diodes across a resistor in the feedback path.
I understand what it makes the op-amp do, instantly skip over any value less then abs(0.5V). What I'm asking is if anyone knows why you would add this to a guitar amplifier to drive a tube.
I have also included a simulation of Switch SW101a, basically how much resistance to ground on the negative input terminal.
The only answer I could come up with is "sound" or it somehow helps correct for non-linear responses in the tube.