Amplifier to pair with NHT 3.3


I'm the proud owner of a pair of used NHT 3.3s. From what I've read I should be feeding them with something capable of plenty of power, but I've got them running off a small crappy integrated amp (30W) at the moment. Any suggestions for an upgrade? I'm looking in the < $500 range for something used. Thanks in advance.
baldeep
Used ... a NAD C370 or C372 (there's a C372 new for $625 on Audiogon now).

Regards, Rich
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.