Recommendation for a highly resolving amp

I don't think the amp is your problem.   I would consider a different pre.

Respectfully, 
Jose

@chungjh If I am not mistaken. You have big speakers in a small room. I believe I recommended in the past you use either acoustic paneling and /or contact Mitch Barnett at

https://accuratesound.ca

to have him measure your room remotely and then have him create Convolution files for your ROON server. So when you stream from ROON to your X1 (before the DAC) your will have the sound optimized for your listening space. This is like using an old time Equalizer but today you do this in computer software.

Some very detailed amps I own or have owned, though I think chasing an amp is not worth it unless you have tamed your room first.

- Benchmark AHB2 (my favorite)
- LSA Voyager 350 GAN (after mods by EVS)
- various Brystons
- CODA #8 (not as detailed but close)

BTW - You replied that you tried Fibre Optic cable. That makes it sound like you tried it and switched to something else. This does not seem correct, because Fibre is so much better than the other connector types. I am not referring to TOSLINK optical cable but Fibre Optical cable.

Upgrade all cabling as Pass 350.5 is  a wonderful sounding amp.

When I tried fiber optic, it sounded a bit harsh and I didn't like the sonic character. I do have room treatments, behind the speakers and on side walls.