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
You have a very nice system so it's hard to say where your issue is. However I would try a Sanders Magtech amp if you are looking for a new amp, they are designed for electrostatic loudspeakers and do that job really well.
why don't you have your buddy bring his amp and pre over to listen in your system.
@chungjh  
Can verify that cubed series is indeed highly resolving. I can hear the difference immediately when I change IC between the DAC, pre amp and my 4B3.  Speakers are magnepan.  Transparency is their thing but I think much is attributed to their patented Salomie input circuit. Have never had the pleasure of listening to a Spectral amplifier.  
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@phcollie.    Have you compared Bryston cubed to other amps?

@mboldda1.  My friend is reluctant to move his amp as it is >60 lbs.