Amplifier to pair with NHT 3.3

For $500 or less, a used Adcom GFA-5500 has 200 watts per channel into 8 Ohms, so it would be even more than that into the 3.3's 6 Ohm load, and it is a Mosfet amp, which is supposedly a little warmer sounding than bi-polar designs.

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 wanted to add some thoughts about using a professional music amplifier and in particular the Crown XLS Drivecore series. (XLS1500-XLS2500)
1. An S/N ratio of 105db A-weighted, though very good, isn't for very High efficiency speakers (It works out fine with the NHT 3.3 at 87db efficiency and even my Taddeo Monitor 1's at 92DB but I doubt it would work well with speakers rated at around 100DB or better as I think you could start hearing too much white noise.
2. Even though these particular Crowns have RCA inputs they need a higher level from your preamp (1.4vrms or better in order to reach full volume capability)than many preamps put out so check your specs.
3. I strongly recommend leaving the amps built in speaker protection turned on as it works very well and these amps are very powerful!

I still love mine and although an $8000 Krell pure class A might be better? I simply can't afford to find out. But it does sound better than an excellent 6550 based Bewitch tube amp driving my efficient old Taddeo's in either triode or pentode mode to my old ears. It just seems to grab the driver's and absolutely hold them to its will.

correction to my last. It's 103 Db A-weibhted s/n not 105. I have since gotten an XLS1500 to drive my VR-2 speakers in another room, sounds great.

The Audio magazine world is full of suspect reviews because frankly the high end expensive equipment advertisements pay a large portion of the bills. Even when not so influenced we all tend to have prejudices and illusions and so do reviewers, who often are ignorant of new equipment requirements and proper matching.

Class D type amps appear to be the future for most of us now. They have truly begun to compete with much more expensive to make equipment. They will only get better in the future.

There is a blog started by a young magazine reviewer, Andrew Robinson, who seems to have run into some negative industrial pressure in the end?
Its a good and interesting read. He discovers more about the amps as he goes along and so do others:
http://www.hometheaterequipment.com/mono-stereo-amps-59/crown-audio-xls-drivecore-series-amplifier-official-thread-1319/

I have found that the Crown XLS-1500 will do just as good a job as the XLS-2500 as it too has more than enough clean clear power for The NHT 3.3's at over 400 watts RMS a channel into the average 6 OHM load of these speakers. Since these excellent amps can be found for only about $250 delivered on the second hand or refurbished market I now recommend them over the XLS-2500 due to price.