This morning I visited a burgeoning new Audiophile in my neighborhood, a 55 year old with a mid-life crisis about to explode, who fell in line with the "the DriveCore 2 amps from Crown are the best amps in the world". He owned three of them in his Home Theater being driven by a Denon A/V receiver's line level outputs. He also happened to have a couple of Parasound New Classic amps in the house which used to be his main amps before "upgrading" to the Crown amps. So, simply put, I listened to them and they functioned just fine and the speakers sounded like his speakers (B&W mid-sized bookshelf speakers, I forgot the models or lines).
When I connected the prior Parasound 275 90 watt amp to the left speaker and left the Crown XLS1002 215W amp on the right speaker and adjusted the gain levels to the exact same gain (used a 120Hz mono signal and used a multimeter to measure at the speaker terminals and adjusted the Crown amp until the two signals were exactly the same voltage), I could tell the Crown amp had more self-noise. While the hiss wasn't obvious at normal listening levels from the listening position, we could both hear the hiss from the Crown amp standing about a foot from the speaker while the Parasound amp required we darn near had to press our ears against the tweeter to hear the hiss. This is not complete proof the Crown amp is useless, but it does show the design differences between a pro-sound amp and a home audio amp.
Connected in stereo for listening tests at pleasant listening levels (in his room the acoustics made everything wash out at the levels which I prefer to listen), the Parasound amp seemed to sound cleaner and more natural - in other words, I thought I was listening to the speakers, room and music and the amp was generally invisible. Calibrated for matching the gain levels (something the owner never tried) and calibrating for the same listening levels, the Crown amp seemed to add some very subtle thickness to the sound. However, I am a skeptic and it is entirely my preconceptions clouded my perceptions of what I was hearing. That said, in the silent passages in the music, like the gap between songs, I could hear the fan operating to cool the amp, which is pretty damning for a super nerd like me. When the AC was on, I could not hear the fan, when the trash collection truck was outside the owner's house I could not hear the fan. When the refrigerator in the adjacent kitchen was operating I could not hear the fan. When there were no other non-constant noise sources I could clearly hear the fan after listening for about 15 minutes at reasonable levels (about 10dB SPL softer than my typical critical listening levels). If I were in a well designed and implemented HT room which should have an effectively silent ambient noise level, I believe the fan would be (figuratively) deafening.
I will say this, the owner was FAR less impressed with the Crown amps after listening at matched levels to the Parasound amp. Because the Crown amps have much greater gain than the Parasound amps he replaced, the SPL in the room was considerably louder than when the receiver was set to a given volume level. In other words, the Crown amps were significantly louder when the receiver was set to his reference level. He had no idea he could, and probably should, adjust the amp's gain controls to at least reduce the noise levels and even more sophisticatedly maximize the volume range of the receivers level control. After perfectly calibrating the levels, the Crown amps sounded more similar to him than he ever expected.
I encouraged him to enjoy his investments, though. Going from a 90 Watt amp to a 215 Watt amp will net him an additional 4dB, or so, of output and reduce the likelihood of clipping from maxing out his amps. His speakers are not terribly efficient, so a bigger amp has some very real benefits for him. I also didn't go on to ask to borrow one of the amps to put on the test bench because he was looking a little like a deer caught in headlights from my inadvertently bursting his bubble. I didn't tell him everything I wrote here, but he could see and hear what I was focused on and made his own realizations.
The room was awful, though. He wife helped him decorate, and it was an acoustical nightmare with the most common and worst aspects of decorating killing any opportunity to make a room pleasing for sound reproduction. It was a terrible. But, he seems relatively happy with things, so I just left well enough alone. He was very disappointed I didn't do my critical listening at significantly higher SPLs, but I wanted to hear the speakers and the detail in them more than the room's washed out bouncy, reflective nightmare.
That's my little review.
To summarize - I believe the Crown amp works perfectly fine and is probably a very good option for an audio enthusiast's first foray into separates do to the value per watt and generally decent performance. It does have drawbacks in the noise floor appears to be higher than even a modest home theater amp and the fan is subtly audible when the amp is in the room. I think I heard a difference in the sound between the Crown and the low end Parasound amps (favoring the performance of the Parasound), so I am reserving judgement on the absolute fidelity of the Crown.
I do know this... I would never ever replace an amp with comparable power output with Crown XLS amp. The higher noise floor and potential for audible fan noise both are enough to disqualify these amps when the benefits are not specifically high power and current capacity.
