Amplifier suggestions to drive a pair of NHT 3.3

I use a B&K ST-202+ (300watts at 4 ohms) FET output transistors provide a warm tube-like sound. When I was a kid I heard Ginger Baker play several drum solos in a small club. When I play his Cream rendition of his Toad solo I am still floored by it on the 3.3's. They are great all-rounders but the bass is magnificent. As for the rough highs I replaced the tweeters with superior Seas Excel t25cf001's and they made the top end softer and more life-like to my ears. Electronically they are pretty close to a drop in so I didn't change the XO but a little Dremel tool work was needed and the flange overlaps a little but still looks good. I like them a lot better now.

Just bought a Crown xls2500 because of good net reports on it and others in various blogs on their drivecore series. I used it to replace an excellent B&K 202+.

Cost new under $600 from local Guitar Center with a free return policy. Less on Ebay.

Result fantastic sound. Can hardly believe it isn't a $12000 Class A amplifier. No white noise even with my ears next to the tweeters and I can't hear the fan even when it comes on and I'm next to it.

I have never before heard such well controlled bass and sweet highs coming in combination from a solid state amplifier into none set speakers. The sound is neutral and flat with no coloration. I loved my B&K's but I have to believe my ears more than my prejudice against pro-audio gear. Check them out, they drive over 400wrms per channel into 8 ohms and almost twice that into 4 or 2

I just stumbled on your post, I LOVE CROWN amps I am Bi-amping a pair of NHT 2.9s with a 350wpc Crown K1 on bottom and Parasound 220Wpc on top, super clean an lots of headroom. An audio engineer buddy of mine swears by Crown and says they are the cleanest of all the pro stuff for the money ( he also has perfect pitch) Enjoy!

No need to Bi-amp with the xls2500 440 watts per channel into 8 ohms and almost 800 into 4. I did bi-wire however. Yours is a good set up though as that Parasound has a good rep. I don't know anything about the K1 though but its a Crown. The XLS2500 Crown drivecore is actually a class d amp but has some amazing specs and probably sounds as good as any of the best money can buy on the NHT 3.3's due to their 6 ohm load and 4.3 ohm dips. I can't hear the fan or any white noise. I'm sure it isn't a good amp for very efficient speakers as the A weighted S/N of 103 db is probably too much for 100 db + speakers but the 2.9 and anything below 92 db should be no problem IMHO. As for distortion there isn't much in the range we can drive them at (yes even with the very loud 3.3) They sound neutral and very clean with a very flat response across all frequency and power levels. Its quite extraordinary for the price and I've been at it since I built my first kit amp over 50 years ago. The xls2500 weights 10.8 lbs and has built in filters and even a special AC power neutralizer too as well as being very efficient. A lower power XLS Drivecore would have done but I wanted the biggest sweet spot I could get as all amps distort their worst toward full power which I never reach due to built is clipping limiters, huge power capability and being able to set the input gain levels so it never clips too. http://www.arccinema.com/crown-xls-drivecore-amplifier-review/

Actually spinster after after looking up your Crown K1 amps
specs I really think it should work better alone driving the your NHT's as it should be a better amp than the older Parasounds in almost all respects. Did you try it by itself? The S/N is a little higher than most newer amps but that shouldn't matter much with 2.9's and the other specs and power range are excellent. Please try it and let me know? It might not sound as tube like as the Parasound but it should be flatter and clearer across the whole frequency,power range:
KI Performance
Frequency Response: ±0.25 dB from 20 Hz to
20 kHz. The frequency response is band limited
with an 8 Hz double-integrated 3rd-order Butterworth
high-pass fi lter and a 30 kHz 7th-order
Gaussian low-pass fi lter.
Signal to Noise (A-weighted): > 100 dB below
rated power.
Damping Factor: > 3,000 from 10 to 400 Hz.