I appreciate all the feedback.
I tried it with 3-4 SET amps actually with unfortunately the same results in each...never had the impact that the all Atma- in balanced provided when being driven single-ended from the MP-1. Perhaps it was just something with mine if others are having better luck.
I sold my Atma gear last year as the amps were more power than I needed and I found a really strong preamp that complimented the SET amps straight away.