What is the best premp for Atma-Sphere MA-1 3.3 amp?

@OP, 
I PM'd you, but didn't indicate the build model.
I own the 3.3 version MP-3.
Also, when I called Atma to inquire about upgrading the MP-3, he said the 3.3 was an entirely different build from earlier models, and to upgrade an earlier model would cost a significant sum. You can see the prices on Atma-Sphere's website.
BTW, one of the reasons you find so many satisfied Atma customers is that you are only a phone call away from help, should you encounter an issue. Most likely it will be Ralph answering the phone, and most likely it won't be the Atma causing the problem- believe me, I know.
Bob

Bob

I agree with you about Ralph. He was so patient with me explaining his circuitry and philosophy. I have no doubt that their quality and service is as good as anyone.

I listen to music via MP-1 and a pair of MA-1 amps. Sounds divine with a pair of 

of Sound Lab Ultimates U1-PX (Ultimate 745).

@gdnrbob 
I am thinking about MP-3 3.3 VS M 1 3.3.

@vittles   

I am thinking about the same system: 745 driven by MA-1. 

1. What is your room size?  Is MA-1 powerful enough for you? Other than loudness, I don't know if MA-2 adds much in SQ?

2. Are you using MP-1 or MP-1 3.3?