best sub $1000 amp to mate with tube preamp

Parasound is fine. I own one. It has a great punch. Bryston is fine too. But if you're looking for a warm natural sound with the same punch, you won't do better than a McCormack DNA-1 for $800-900. You might do better with a Levinson, but it'll cost you. There's a used DNA-1 for sale right now for $850. Poke around in the forums and read the glowing comments. You won't find anything in this price range that compares.

I agree with Csericks (Customer Service Engineer Ricks?) and Tvad. Assuming what ever you'll be looking at will be used, it's difficult to better the sonic virtues of class D amplifiers at this price point. I drove my 4ohm, 87dB sens. Avalon Eidolons with a PS Audio HCA-2 with ease.

On the linear amp side for $1100-1400 I would suggest the Ayre V-3 for its ability to dive difficult loads and its wonderful presentation.

Can't speak for the other suggestions, but the tube pre(TAD 150) & McCormack DNA-1 deluxe sounds sweet to my ears...running 86dB speakers with no effort, nor needing anythng over 10 o'clock on the volume knob.

I don't know about best, but, the c-j solid state amps have a fairly high input impedance, are not overly sensitive (so they don't pick up and amplifiy a lot of noise) and are designed from the get go to work with their own well regarded tube pre's. Some, but, not all of the McCormack amps have similar qualities.