Recommendation for a highly resolving amp


I have Don Sachs 2 tube preamp driving Pass Labs X350.5 driving Sound Lab M545 ESL speakers. I like the sound very much, but when I went to hear my friend’s Spectral system (driving Quad2912 ESL) I realized my system can benefit from having a higher resolution amp. Spectral amps need all Spectral preamp/cabling, which would be quite expensive. What would you recommend?
128x128chungjh
I don't know your budget but a Luxman m-900u is a solid contender. Very resolving but never neutral or dry.
@chungjh   are you sure the issue is with the amplifier and not with room and speakers?  
or possibly the preamp or preamp tubes?
have you tried different tubes for the sachs preamp?  
most 6SN7s can be overly smooth.  
just trying to help you avoid chasing the wrong dragon.  
@chungjh Are you streaming with Fibre into your Lumin X1. If not that would be the first thing I would do. Pretty simple and cheap to set this up with a Network switch that has Fibre outputs. This could make a big difference depending on the quality of your Ethernet setup.

Then try different amps.

it all starts in the front end but if its good next are the amps
my amp and preamp are Aesthetix very resolving

Enjoy the Music 
Tom