What is this part of the Boss DD5

[vondran]

I'm trying to understand what Boss is doing with the circuit that feeds into the "AINL-" input (left input) of the AK5345 IC.  Specifically, it's an op-amp circuit with 8:1 gain (82K/10K) and clipping doides.  It's clear that the clean signal goes into "AINR-" input (the right input).  So why would they boost the signal and clip it to feed into the left?

[anchovie]

Hard to say as the effect is driven by a microprocessor and some code. It might be used for some kind of compression or noise suppression algorithm - if the signal amplitude equals the clipping threshold of the diodes then it is "healthy", if it drops below that then "do stuff".