Help understand the workings of the signal detector opamp circuitry.

[Yamin]

Hi guys,
I am working on restoring a bass amplifier. I am trying to figure out how the circuitry which detects the signal and  which detects clip circuitry works. Its working fine but would like to know how it works. It looks like an inverting amplifier but I am not sure whether I am right and also what is the purpose of D29?
I would greatly appreciate if you could help me understand how these two circuitry work and also advise on further reference would be appreciated too.
Thanks in advance.

[Kibabalu]

Are the opamps supplied single or dual?

In this case the two opamps are pursued as comparators with hysteresis resp. as Schmitt triggers. The function of the diode in the positive feedback path is unclear to me. I guess it gives non-symmetrical hysteresis points. Maybe somebody else knows more!

[Yamin]

Are the opamps supplied single or dual?

In this case the two opamps are pursued as comparators with hysteresis resp. as Schmitt triggers. The function of the diode in the positive feedback path is unclear to me. I guess it gives some kind of a 0.7V offset for one of the hysteresis switching points. Never have seen this before. Maybe somebody else knows more!

Thanks, the op amps are supplied from +/-16V. Can I please ask what you meant by "hysteresis resp."?

Thanks again

[Kibabalu]

Are the opamps supplied single or dual?

In this case the two opamps are pursued as comparators with hysteresis resp. as Schmitt triggers. The function of the diode in the positive feedback path is unclear to me. I guess it gives some kind of a 0.7V offset for one of the hysteresis switching points. Never have seen this before. Maybe somebody else knows more!

Thanks, the op amps are supplied from +/-16V. Can I please ask what you meant by "hysteresis resp."?

Thanks again

resp. is the abbreviation of respectively.

What I meant was that "Schmitt trigger" is just another description for "comparator with hysteresis".

Sorry for writing not clear enough!