For me, what is jumping out at me is that I don't see guys with experience in using Crown amps in an audiophile setup. That doesn't mean that the Crown stuff is no good. I think it means that there's been a bias against using pro gear in audiophile setups. I'm getting more and more curious if there's anyone who has really done a solid review of this? Any way to make that request up the food chain so that we can see an audioholics amp test using Crown pro gear vs. audiophile amps?
There is an extensive thread on Audiokarma forums with regards to the Crown Drivecore XLS... at least one of these was purchased, and the travelled through the US based audiophile community with people trying it out on their various setups, and commenting on the results.
The results were overwhelmingly positive, and many people ended up purchasing their own XLS (including me)
My speakers are Gallo Nucleus Reference 3.2 - which can be a difficult load as the impedance drops to 1.6 ohm - lots of amps just don't sound great with them...
The Onkyo SR876 and Integra 70.4 AVR's I had were capable of 165W@8ohm stereo RMS.... and sounded good with my speakers - but the Crown XLS2500 which I purchased used (US$250 !) was just as good, and appeared to have better dynamics and more headroom... (which at 440W@8ohm is not surprising).
Both the older AVR's had substantial power supplies - I also compared the AVR's and the Crown XLS to my Quad 606 current dumping amp (rated at 135W @ 8ohm, "unconditionally stable into any load" ) - I felt that the Quad was perhaps slightly smoother than the AVR's in the midrange, on a par with the Crown, and I probably could not tell them appart in a blind test.
More recently (last 12 months) - I replaced my elderly AVR's with a current generation Integra DRX 3.4.
It is rated 100W@8ohm - and is rated to handle 4 ohm speakers (purportedly) - my speakers are 4 ohm nominal.
It sounded like rubbish - it was congested, soundstage collapsed, imaging was gone...
My suspicion was that the power supply was too small, and it could not supply the current needed for the 1.6ohm nadir of the impedance curve.... so I plugged in the Crown XLS2500.... kept the AVR as a prepro - the sound immediately cleaned up, and became the sound I was expecting from my system.
I also tried the Quad 606... which also worked well - but the Quad is likely to be close to its limits into a 1.6 ohm load. It is rated 90W @ 2ohm, which roughly speaking equates to only 22.5W @ 8ohm - so peak SPL would be limited... although above my normal listening levels, it still feels better to have additional headroom... so I have set the system up using the Crown as my main stereo L/R amp, and leaving surround and height duties to the AVR's internal amps.
Downsides on the Crown Drivecore XLS amps - theoretically, there could be fan noise - the fans on mine have never been audible... but then at absolute peak (ear splitting) levels, the -20db LED barely lights up... so at absolute maximum I use 16W of the available 440W... the fan probably never needs to spin up!
Another issue for some people, is the DSP - the XLS digitises everything and it passes through the DSP - which limits frequency response to 22kHz (presumably standard 44khz 16bit ADC/DAC) - and yes there is no option to bypass it (at least on my first generation model)
There is adjustable gain (via a dial for each channel) - but max rated power out is achieved with an RMS input of 1.4V - so your preamp needs to be able to provide a clean 1.4V to maximise performance.
Some people that have run it with gain at max settings, have complained of hiss, I run with the gain knob set at around 75%, and have not experienced any hiss at all (no matter if I put my ear to the tweeters).
Note:my Prepro has been measured as capable of putting out around 3.5V from the pre-outs.... in any case there are no gain matching issues (hiss is usually a gain related problem!)
The DSP also allows crossovers to be set between the two channels, allowing an XLS amp to BiAmp a speaker properly, as you can fully set the crossovers within the power amp... (yes that is one of the reason I tried them... I was looking to eke out more performance from my speakers by Biamping... but I found that the difference was minor, and possibly completely imaginary, so I set things back to normal amping, and simplified the wiring! - with less powerful amps, Biamping might provide benefits, but when the base amp is 440@@8ohm and 1200W@2ohm, it makes less of a difference)
For audiophiles on a budget, I highly recommend the Crown Drivecore XLS amps - they are often available cheap in environments focused on pro-audio... garage bands come and go.... and they resell their amps! - that's how I got 2 of these for US$250 each.