> When I was working on my so-called project I've read, for instance that 4558
> op-amps sound crappy, and that NE5532 or TL072 were much better ones. Without
> knowing what exactly these amplifiers are or how they work I tended to think
> it could improve the overall P6 sound if I would have changed them all...
However the 4558 on the KLM-367 are not in the audio signal path; as far as
I can see most are just buffers for the control voltages. There will
probably be very little to gain by exchanging them.