Topping Pre90 Switching op amps?

If you want the sound of the pre90 without the hassle, then the Benchmark LA4 is the best bet.

True but the price differential was unacceptable.  (I needed 3, now 4.)

Nota bene:  The OP was asking about swapping op-amps in the Pre90, not amps to connect to the Pre90.

"Nota bene: The OP was asking about swapping op-amps in the Pre90, not amps to connect to the Pre90."

Thanks kr4. For a second there, I thought that I was losing it, and the funny thing is that the OP didn’t correct them.

@roxy54 

Yes. It was a digression, but interesting nonetheless. My question is on op amps, not amps.

I am running the Topping PRE90 with a VTV Purifi Eval 1 and I agree with your assessment regarding it be the incredibly transparent to the source but can sound thin or brittle. I remedied that with a Jolida SSX tube buffer and it renders the music with more body and tightens the bass. It's the best my system has sounded. Maybe this might be a direction for you rather than swapping opamps.

@rrboogie 

Did the tube buffer reduce the transparency by a noticeable amount? The idea of a tube buffer occurred to me but I thought it would necessarily add some haze given tube equipment generally has higher s/n ratios.