Theta Enterprise or Ayre V1x with Vandy 5A

From what I have heard, I would tend to agreee with both driver and rex. I had not heard the V5x to be at all lean in midbass. I would double-check speaker setup, cables, and room treatments before I moved on...

You might want to check the following things on V5s for mid-bass issues:

(a) High Pass Filter Dip-Switch Settings - need to make sure you are changing this as you try different amps as it affects mid-bass directly (be sure to adjust if amp specs given for Single-ended and you are using balanced cables)

(b) If you are already adjusting this and are still lean in the mid-bass, you may want to try a setting one step down from the suggested setting for your amp's input impedance

To increase mid-bass you can also try the following in terms of speaker positioning:
(c) Can bring speakers slightly closer together, try in 1/2" increments for each speaker

(d) Can move speakers slightly closer to wall behind them in 1/2" increments

(e) Can increase toe-in slightly in 1/8" increments (measured to side wall from speaker corners)

(f) Can put "disks" or "pucks" under the spikes if you have a suspended floor (wood) in your listening room

Good Luck!

I have not tried the Ayre, but I do own a pair of Enterprises (which drive my Thiel CS3.6's). I had set off on an amp quest which I thought would end in the purchase of a high end Krell or Edge amplifier, when I had an opportunity to audition the Enterprises. What sold me on the Theta's was the incredible soundstage width and depth, the separation of multiple instruments, and what I consider to be a very musical midrange and top end (for SS amps, of course). The low end is not Krell-heavy, but it was every bit as good as an Edge NL-10, and again very accurate - upright bass sounds like upright bass, electric bass sounds like electric, etc. I know that Mike Fremer's review of the Enterprises was somewhat critical of certain aspects of the them, but if you really read his review, his main complaints seem to fall within the "tube vs SS" realm. All in all, I thought his review was quite favorable. What was also important for me (as I will be running these amps inside a cabinet until my kids are a bit older), the Theta's do not run hot at all.

I have only heard good things about the Ayre, so I would think that the V1x would also be a good route. But, for what it's worth, I am a very happy Enterprise owner (and the CS3.6's are not the easiest speaker to drive).

Thank you all so far for very informative responses.

I have owned both the Enterprises and the Citadels. The Enterprises are nice but to compare them to the Citadels there really isn't much of a comparsion there is nothing the Citadels cannot do, the highs are great the bass is so taut, transparent, soundstage is so large and deep-in another world i could go on and on a true high end amp.!!! The Ayre will not be in the same league with the Citadels. If u got the money get them!!! If not get the Enterprises which are quite good. Citadels are one of the top amps ever made all reviews rave about them and they are that good find a pair and try umm!!