Phoenix Gold Phorum

Hello to everyone.

As I learn from phorum and some people.
There is 11 BA4560 op amps inside of M44 and 2 BA4560 op amps inside of M50.
For M44 7 opamps are for the 4 channels signal and bass boost, the 4 for the xover.

For me , There are 2 option. 1642 or 2134

1642 is looking superior than the 2134 but needs more labour to make and install. But OPA1642, They are a soic parts so you need a soic to dip adapter.

It is necessary to pay attention to V+ and V-. Are there any examples of any of these processes(OPA1642 or 2134) being done?

I need your support on this matter.

Many years ago I played around with changing out op-amps on my PG amplifiers.
I never noticed a difference in sound, or performance.
Now you can make the argument that my ears are not good enough to notice, and someone else's are, and that is a fair argument.

I think I can instead back up my point with a little more science.
PG used op-amps in high feedback conditions. The whole point of feedback is to make up for deficiencies elsewhere, and improve the signal quality.
Allow lower quality parts to perform better seems to be the goal.
At the time I was playing around with changing out op-amps, my research steered me towards high end headphone amplifiers. These headphone amp designs were low feedback designs, so the quality of the op-amp was critical to the performance of the amplifier overall.

When you install a high end op-amp in a PG amplifier, the feedback of its design will limit any performance improvement the op-amp could offer.
You would be better off trying to modify the circuit design to remove the feedback, and then you could actually make use of high end op-amps.
My guess is there would be a lot of issues keeping the circuit stable in that case though.

Either way, good luck with your plans, and please report back your results.