Preamp recommendation

Wow, did your budget go up? lol.

The sound between the A51 and A52+ is going to be very similar (if not the same).  The main difference is power / power supply.  Your Focal Dome speakers are not going to be too terribly hard to drive, so the difference between 180 watts per channel and 250 watts per channel is not going to make any significant amount of difference (in my opinion). 

The higher power of the A51 would be beneficial if you really large woofers and low impedance speakers.  The A51 might be just a little bit more smooth and full, but it is a significant amount more.

I find that budget always goes up no matter where you start, at least this is true for me. I think I'm leaning to Parasound P7 pre, and Krell KAV500 vs. A52+. 

Before making a final decision, I'm also looking at Anthem MRX520. Do you think the sound from Parasound/Krell would be better than Anthem via Focal dome speakers? Anthem reportedly has good room correction (ARC). Not sure how much of an effect that will have on sound. 

BY THE WAY: My older Krell KAV500 failed on me a year after I got it, needed to be recapped and again, one year later making strange popping noise through speakers while its on. I love the sound of Krell via Vienna acoustics speakers. 

The Anthem MRX receivers are very good and have very high resolution speed and attack.  The downside is that in some systems, the Anthem could sound too bright/harsh on the high frequencies.  This could definitely be the case with your Focal. If you went this direction (and possibly with the Monlith amp), I would recommend some nice copper solid-core speaker cable, such as Audioquest Rocket 33 or Type 8 or Type 4.  Also, use gold-plated terminations instead of silver.

The Parasound would definitely be more forgiving on the high frequencies.  You will likely have to spend a lot more to get a high resolution amp that is not bright, and you also should still avoid stranded speaker wire with anything silver or silver-plated.

If you are wandering around in the budget area of a Parasound A51, there is a Chord SPM-2400 five channel amp on audiogon for $2999 from a dealer.  This would be the next step up which would give you excellent resolution without being bright/harsh like the Anthem or Monolith.  It would not be warm with soft/rolled off highs like the Parasound.

Found a classe ca-5100 amplifier, brand new, NOS. for $2.5k. 
Anyone know this amp? Would it be a good match with Parasound P7 and focal speakers ?