Topping Pre90 Switching op amps?

I have found that the pre90, in my system, renders many recordings beautifully transparent and many other recordings thin and brittle. It seems that swapping op amps might be a solution. Has anyone done this? If so kindly report on your experience. 


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.


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.

@dbb Surprisingly, it did not not reduce the transparency. I can still hear all of the details. I am using Altec A7 speakers which are over 100db efficient and it added a slight bit to the noise floor but you need to put your ear up to the treble horn. Preamps I had before this were Pass Labs X1, Modwright LS 36.5, Black Ice Audio Fusion F360. All had a higher noise floor. I tried the Topping D70s direct which was excellent on it's own and lead me to the PRE90 which on it's own is dead silent. 



Does the pre90 remote work well on yours. Mine, as reported by others in reviews, works poorly. I wonder if this issue has been fixed in newer production models.

The remote is weak. Not great off axis. I use an infrared repeater and it works great!