Help with opamps in amp circuit

[Soundcard]

Hello I've got this amp and there are several opamps in the pre stage. I have attached the schematic of one channel of the amp including opamps.

My first question is can anyone figure out what is the gain of each opamp in this circuit ?

Another thing is do you recommend any modification to the circuit if I were to replace the original opamps with newer variants (such as OP275, or OPA2228, OPA2134 OPA2604 etc.) ? I read that potential problems are either insufficient power or oscillations for newer opamps. I would use sockets so I can keep the best variant at the end.

Thannks for the support

 

[ostripper]

mitsubishi soft switching circuit , similar to" class super A JVC".
A circuit like this relies on the low slew and BJT Vbe of this old op-amp.
Circuit wise the M5218P = a LM/ua741 almost exactly.
To replace with a Jfet/CMOS op-amp would most likely fail.