Can pro amps possibly sound good? Crown, QSC, etc

I have been looking into pro amps for a to-be-built HT/music room. Recently I came across an old review in The Stereo Times: The Complete Audiophile Magazine, which reviewed 2 discontinued Crown amps, the K2 and the Studio Reference I. The K2 the reviewer thought "not distinguished or especially musically refined", but the Studio Ref he thought an EXCELLENT full-range amp. It does have some amazing specs:

Signal-to-Noise (A-weighted) below rated full bandwidth power: 120 dB.
Damping Factor: >20,000 from 10 Hz to 400Hz.
780WPC into 8 ohms, 1160WPC into 4 ohms.

The review is here.

From what I've found so far, there are possbile downsides to using pro gear in an otherwise consumer setup, but in my case I think these are non-issues:

-fan noise: not an issue for me since I will have an equipment closet. Won't have to do a "fan mod".

-ugly: again, not an issue for me with an equipment closet

-hum: I believe not an issue as long as I use balanced interconnects from the prepro. Someone correct me if I'm wrong.

-expects pro-level input levels: I think not an issue if the amp has dip switches or gain controls?

And yet, over on a couple of AVS forum threads, I actually got asked to leave when I started suggesting pro amps. It seems as though some of the audiophiles there (and the same guys might be over here) don't even want to hear about a class of gear which imo just MIGHT sound good. It just isn't worth "polluting" an audiophile thread. Am I missing some other downside to pro amps, other than the above pints? Were these guys attitudes based on something substantive and audibly detectable, or just a form of audio bigotry?

I'm not saying all pro amps are going to be great (for instance I know the Behringer A500 is lousy), but might there be some good stuff too, like QSC DCA, or Crown Macro Reference (other suggestions would be welcome)?
Not mentioned in your post is quite possibly the biggest reason pro amps are not desirable for a high performance home set-up. Pro amps are designed to be super reliable since they are often used by on-the-road musicians and thrown around from gig to gig. They are often overdriven, run in hot environments and operated less than ideal AC power. Therefore, the manufacturers design their products to be bomb proof and unfortunately, sound quality suffers because the parts they use are more reliability oriented and not necessarily chosen to be the best in terms of sonics - it's a trade off.
Oops the last line should have read "Macro Tech" rather than "Macro Reference"...the latter is discontinued.
I have heard the Master series should be the most "Audiophile" sounding of the Crowns.. However I have heard some Standard QSC amps that are pretty good for way less money.. The K2 is a great amp for certain applications and is Fanless.. That’s the main Stigma of most PRo amps that they are Noisey from internal Fan cooling so watch out.. Also most do not have anything but 1/4 " and XLR pro connections on the back, so adapting them to run with your standard equipment can have its faults.. Beyond that many Pro amps take 4 volts to drive to Full power from a Preamp or source and many consumer or hi end players only put out 1 volt to 2 volts… Then you need a device between that’s made by companies like Rolls that can actually up your output signal by taking in a RCA and spitting out an XLR connection to the amp putting out the 4 volt conversion.

And Like the Crown K series I know that if you run them Single ended not Balanced they are only a 10 k impedance at the inputs, but if you can run balanced XLR without cheater plugs you will get a 20 k input impeadance which is much more universal, 10 k is pretty low for many Preamps to drive, especially if you use a Tube front end, so this can cause a limited bandwith and output as well in some cases..

In the end, if you can get a deal on a nice consumer grade amp go for it over all the extras sometimes needed to attempt the pro amp route, again the application and your situation will need to dictate whether its worth a try or not.. Some speakers might work well with pro sound and some not. That’s my opinion.
Pro amps are like everything else- some are good and some are bad. There are no issues with using them at home most of the time and often they can be had for far less than comporable audiophile jewelry.

I would not intentionally avoid pro stuff. I would just investigate residential use on a piece by piece basis.

Crown have been used to power main monitors in custom built studios for many years. If you are looking for dynamics then the power and headroom may come in handy in an HT setup. (Movies are not nearly as compressed as most music so dynamics/headroom is relatively more important. In studios where sound is live and uncompressed - the extra headroom can be critical)

What you will probably find is that at lower volumes the Crown will not be as refined as an audiophile amp - but at higher SPL it will seriously outperform an audiophile amp (in similar price range of course) For example, my power amp to the main speakers run in Class A until 2/3 power or up to around 150 watts, which is more typical of an audiophile design (performs better at low volumes).

The key consideration for any amp is to give it an EASY load. All to often difficult and complex speaker loads are the cause of major problems. Some speaker manufacurers seem to be competing today to actually give amplifiers difficult loads - due to the specifications game of bass extension and frequency response brochures (buyers often don't consider the load and speaker manufactuers like to just assume that you can find a perfect amplifier (and perfect amps do not exist)!
I use a Crown XLS-802D ($599.00 retail) to drive my living room and patio systems at home, and it sounds excellent, even though this series is often derided since it is made in China. It pumps out 800 wpc into 4 ohms, 500 wpc into 8 ohms. I run it off my Supratek Chenin tube preamp with no problems - the output of the Chenin is split so that half goes to the Crown and half to my main rig. In the living room it drives Magnepan MGMC1 speakers with a powered Monitor Audio R720 sub, and on the patio it drives KLH outdoor speakers and a passive subwoofer. It is driving all this through about 200 feet of CL3R in-wall cable and two Niles impedance-matching volume controls (set to 2X setting) and doesn't even break a sweat. Not quite the sound quality of my audiophile rig in the family room, but pretty darned close for the money.

It is built very solidly, with large heat sinks and a huge toroid. I think Crown has made several improvements to this series between the 802A and the 802D, and I am impressed by what I got for $599.00
Oh, and I forgot:

Crown was offering a $120.00 mail-in rebate at the time, so the actual price ended up being $479.00. Outstanding value in my mind.
I owned clubs. I've had Crown, Crest, QSC and more. I still have a qsc running my whole house audio (quality is marginal with in ceilings anyway). However, I really don't like the quality of sound compared to most mid-fi amps. I have a PSE Studio IV for sale and a QSC 1200. I'll take the PSE with 100 watts over the QSC 120 watts any day. Much more detail, better soundstage, and yes a little softer/more forgiving/not rudely revealing.
My big Crest amps were awesome for $4000 each. But that's ridiculous for home. If you are spending that, get custom engineered JBL or Genelec speakers made for the room too...
Ok, I went home to prove to myself that I wasn't full of it. My PSE is worth about $375, QSC worth about $300.
I did a side by side test. It was like night and day. My dog could tell the difference...Needless to say, the QSC is for sale. Besides raw power, a cooling fan and being a bulletproof sub amp, it sucks for stereo listening or theater.
And, I did the side by side using a Denon multi room receiver and Paradigm in-walls. Imagine how it would do with my AR pre and Sota table?
I was at a outdoor party a couple of weekends ago and the DJ had some pro audio gear and I was really impressed on the quality of sound, lots of detail, and at a low volume. I was curious so I decided to look and see what he was using in his setup. The amp what an older version Tascam, a cheap cd player and was using a crate equalizer. I started looking for pro audio gear on the net and there are two pro amps I am considering, QSC RMX and Face Audio. Face Audio is a Class H amp with zero distortion. I might be consiering the face audio, still doing more research. David
I have three CarverPro ZR1600 amps and five Channel Island D200 amps, and each set of amps has been used in a multichannel system using Maggie MG1.6 speakers. The ZR1600 is juat as good as the D200 (which is a well regarded "audiophile" amp) and delivers more power at half the cost. Gain is easily changed to suit need with a jumper plug, and fan noise is not a problem because the amps are in the cellar. My ZR1600 cost slightly more than $2400 for three. Current price is a bit more. What a deal!
Maybe it's the really nice front end stuff I have feeding it (Zero One Mercury CD/HD and Supratek Chenin tube preamp), but the Crown sounds fine to me for casual listening. YMMV
Thanks for all the input, guys. From some of the not-so-glowing commentary about the lower end of the pro gear spectrum, I guess I'll be avoiding the low end, at least for the fronts, and probably the sides and rears as well. So the real question becomes whether higher-end pro amps (since QSC, Crown, Crest, etc. have lines at different price points) might sound comparable to respected audiophile gear. Some background: I am currently thinking of Revel Ultima2 Studio2 and Voice2 for my fronts. These are 6 ohm nominal and rated to 500W continuous but I want to have at least 750-1000W into 6 ohms on hand for short-term peaks. Something like the Bryston 7B-SST or 14B-SST establishes the low end of what I want to have as far as power (600W/8ohm - 900W/4ohm) and at $3000 street per channel may be beyond the very top end of what I might spring for pricewise....I'd rather keep it to $1000-2000/ch. Hence my interest in pro amps.

Elevick - do you know which Crest product line it was that you liked?

Seasoned - It is a reasonable theory, that the need for reliability and (usually) low weight will restrict the choices avaible to a pro amp designer, which could have audible consequences. I guess me feeling is that first, I wouldn't mind having something that, in a home environment, may last me a lifetime. Second, I have a theory that might counteract yours: I think that the audiophile amp designer's budget has bigger pieces allocated to making the exterior look pretty, and to marketing dollars; additionally, the audiophile amp company probably enjoys lesser economies of scale, and so may not be able to get as good pricing on parts as the big pro amp companies. So I'm wondering if, by spending enough money on parts (which should be possible for the higher end pro product lines), the pro amp designer can design a product that is reliable and light, but without significant impact on sound quality. Just conjecture on my part.
Ait - you wrote "Not quite the sound quality of my audiophile rig in the family room, but pretty darned close for the money". It might be a hard question to answer, but could you please try to characterize the difference in sound? And what audiophile amp are you comparing the XLS to?

I run the Gilmore Raven amp in my main rig, with Zu Druids. Since I'm using different speakers in the LR and patio, extracting what part comes from the amp and what from the speakers, cable, volume control, etc. is impossible, but I don't hear anything from the LR and patio systems that I would deem offensive, let's put it that way. I have not substituted the Crown for the Gilmore in my main system, mainly because the required cabling is different (XLR versus RCA) and I'm too lazy to pull it all apart and put it back together just for curiosity's sake.
If a piece of "pro" gear meets your criteria for "good", fly with it! I've been using a Hafler TransNova 9505 to bi-amp my woofers with for years. It's a "pro" studio amp(though not a particlarly inexpensive one), and I couldn't be happier with it's performance, in that capacity. I might even be able to live with it full-range, if I absolutely had to.
Surprised the Applied Audio Research Labs SLA1 or SLA2 have not come up. You can get the SLA1 for $189 and it is 100 watts per side. The SLA2 is 200 watts per side and $289.

These are 80-85% as good as many great amps I have owned. Every Aphile should have one around. They are just awesome.

When folks hear them they are floored.


If you have not bought your Revel's yet then why not consider Active speakers ? If you are looking at pro amps then why not check out the speaker section at your local music store - listen to the Genelec 8050A and see what you think....Revels are pretty neutral as far as audiophile speakers go - so pro speakers may be up your street! Just a thought. Listen to the quality of the bass and midrange of these speakers - damn good at any price. (but they come at a very reasonable $4.5K for a pair new and no need for a power amp!)
Oh and before these speakers get dismissed as crap along with other pro gear just take a look at Blackbird Studios in Nashville - especially Studio C designed by George Massenburg - you will see a cost no object setup and guess what - Genelec 8050A speakers for near fields.
Thanks again for everyone's thoughts. Grannyring - thanks for the suggestion, but I'm not looking for 80-85% of the performance of "great amps" for $200-300 per channel, but rather (I'm hoping) 99-100%, for up to $1000-2000 per channel. I'm wondering how a $1200 QSC PLX3602 or $1600 QSC DCA3422 is going to sound vs a $6000 Bryston 14B-SST, for example. I know the Bryston has somewhat better specs, but is QSC already at the point where differences are inaudible? Unfortunately, the Crown Studio Reference I posted the review of is discontinued.

I have my doubts as to whether I would be able to discern differences by auditioning different amps in different locations with differing associated gear and acoustics.
Shardorne - in fact I currently have actives in a 2.1 setup, the Paradigm Active/40s. For the new HT, at one point I was looking into smallish actives like the JBL LSR4300 series, and the Focal Solo6 Be (if people aren't aware, these list for 45% less than Focal Electras with the exact same drivers, and you get the amps thrown in for free). Anyway, I started becoming more concerned about SPL capabilities, and turned toward the Revels. Pro active speakers are still a possibility, but if I go that way I'd go for the higher SPL, 3-way midfield or "main" monitors. The thing is, these are designed to be flush-mounted, and at this point I think I'd prefer free-standing fronts.
Pro active speakers are still a possibility, but if I go that way I'd go for the higher SPL, 3-way midfield or "main" monitors. The thing is, these are designed to be flush-mounted, and at this point I think I'd prefer free-standing fronts.

They are not intended to be flush mounted but like any box speaker they will invariably sound better that way (no baffle edge diffraction and no comb filtering suckouts in the bass frequencies from rear wall quarter wave reflections).

The ugly boxy appearance of regular pro speakers and extreme prices of aesthetic consumer versions of pro main monitor speakers is the biggest hurdle - so I understand your dilemma.

HOwever, if you truly desire high amounts of SPL with crystal clear low distortion and low dynamic compression then I would urge you to think pro speaker models - most consumer gear speakers are not intended to sound good at high levels and most of the construction costs go into the high quality aesthetic appearance (beautiful finish) and not so much into the driver build quality. At moderate SPL levels the best audiophile speakers will be comparable or can often surpass the best pro designs - so what SPL's you desire to achieve is an important consideration.

Hooking up mega power amps to consumer designs to get high SPL's is, IMHO, a will be disappointed by the dull sound of the drivers as they exceed Xmax and as their response compresses thermally.
To clarify the AR SLA 1 and SLA 2 amps are stereo amps that can also be switched to mono operation. When I say 85% of the best - I mean the best. 85% to me may sound like 95% to you - very subjective.

These amps will sound as good as any $2000 amp listed thus far on this thread. Spending more on the amps listed thus far will not get you better sound.

No pro sound amp will sound 99% of my TRL amp. That is simply not available right now. The AR SLA amps will get you as close and closer then the higher $$ amps mentioned thus far on this thread.

Try one!


Thanks, what you've said is going to make me revisit the possibility of going with flush-mounted speakers. Do you have any opinions as to sound quality of various pro alternatives, Genelec, Adam, Dynaudio, etc?
Grannyring, thanks for the suggestion, but 200W/ch isn't enough power for me. And I'm told that bridging increases distortion. I'll keep an eye on their website, assuming I go ahead with separate amps rather than active speakers, to see if they introduce higher-powered units, as it will be some time before I design and build the room itself.
There are a variety of things that make this Crown K2 amplifier less likely to be as good sonically as audiophile amplifiers. They are:

1. This is a switching amp but they don't give the details on power supply or output stage technology. The problem is that even in the audiophile world where innovative companies like NuForce and Jeff Rowland have designed high-end digital amplifiers with a focus on sound quality above all else, the results have been mixed. There isn't anything near consensus that these audiophile switching amps are capable of equaling the sound of conventional amplifier circuits.

2. A very high damping factor spec is a red flag for the use of lots of global negative feedback which causes fatiguing and unnatural sound. (See the other many threads about the pitfalls of global NFB)

3. Amps designed to make huge power like this Crown K2 (especially when they are not terribly expensive or heavy) sacrifice finesse, transparency and resolution at low and moderate (read: normal) household listening levels. These pro amps are designed for much larger environments and much higher SPL's than should ever come in to play in a normal home listening environment.

4. The frequency response spec shows that these amps are intentionally bandwidth limited with high-ordered filters. This will cause all kinds of phase shift within the audio band. Today's best sounding amplifiers have extremely wide bandwidth and are not bandwidth limited for a reason.

5. The K2 features all kinds of protection circuitry which is both unnecessary in a home application and not sonically benign.

I'm sure there's plenty more to pick at, but Crown doesn't give enough details about the amp. Generally though, pro amps have very poor parts quality compared with audiophile amps and my guess is that the same holds true here.

Remember, most listening we do with our home systems doesn't require huge power, ultra low impedance drive, protection galore, or extreme cooling capabilities. These are all primary design goals for a pro amp yet they are secondary considerations at best for a home amplifier. Couple that with the fact that home loudspeakers have become reasonably efficient with benign load impedance and you realize that quality is more important than quantity (power) at home.

Do you have any opinions as to sound quality of various pro alternatives, Genelec, Adam, Dynaudio, etc?

Speakers are very much a matter of taste. Obviously I like the recent Genelec 8050A - I am not partial to older Genelecs however - so discussing a speaker brand is difficult. Dynaudio is bass heavy and so is PMC - if you like a heavier bass then these are worth checking out - both are excellent and probably closer to the sound most people desire today. Adams use ribbon tweeters - nice sound but I prefer a polite silk dome tweeter to these - again a matter of taste. Also checkout ATC Actives if you can find any to audition - they probably play louder more cleanly than anything except for horns.
What is the standard? If you are hearing EXACTLY what the musicians heard in the studio, then you are hearing the music as it was intended to sound.

That's why I think good quality studio monitors are far, far better than most "audiophile" speakers -- and generally far less expensive. For less than $3K you can get a pair of JBL LSR6328Ps with 370 watts of Crown power in each; uber-flat response, and amazing detail. For another $1500 you can add the 12" sub.

Good pro amps sound good. Just like audiophile gear, some is all show, no substance. The best stuff is not necessarily the most expensive. Hafler amps, at the end, were pro amps, not audiofile amps, yet were great. Crown has made stunningly good amps and some really lousy ones (the PSA2 with switching power supplies, early 1980's).
I saw where Crest Audio amps were mentioned here, unfortunately,no model number was listed. I've got an older model Crest Audio 4000 professional amp that I could use if possible. Not much info available online about this particular model, most likely because it's so old and forgotten. One guy did say that from what he remembers about the 4000, it used quality parts and had a HUGE transformer. Seems like most people recommend QSC or Crown amps when using pro amps in HT.
QSC and Crown to a degree are almost "pro-sumer" and the stuff they sell for DJ and live sound reinforcment is just that- it is PA gear and will not give exceptional detail sound that we as audiphiles expect.

I have tried a home system with amps from now defunct AB International. I'm sure the build and parts quality are just as good or better than any home electronics . The thing weighed a ton and could drive anything. Hooking it up was no big deal for me. I mainly XLR anyway. But the sound was somewhat PAish. It would be good to drive some PeeVees for a backyard party or something.
The Crest amp I have is called the P4000. I can't find much info online about it and Crest Audio's website doesn't seem to keep much on older gear.
Considering the largest QSC amp to run the low end. 22-39hz in a biamp configuration

With lucious tubes on the top would the QSC work or detract from the presentation?
The reason people are considering pro amps at all is the ludicrous prices of audiophile power amps of any decent power (e.g.300w per side at 8 ohms).

Im a live & studio sound engineer of 35 yrs, but I'm an audiophile at heart. I would concur that the necessity of bomb proofing pro power amps with a variety of protections doesn't lend them to suitability for critical home listening, not to mention the fan noise often present. Before there were dedicated pro amp manufacturers, the pro industry used Phase Linear 700Bs a lot, though being a hi fi amp they proved to be too hard to maintain & too devoid of protections for pro use.

I've been thinking of buying a used Crown Macrotech 1200 to drive my Earthworks Sigma 6.2s, but won't have a chance to hear it before purchase so am going off the idea. I'd love a Bryston 4B ST, but just too expensive. Any suggestion of great sounding 300w per side @ 8 ohms power amps that aren't in the multi $k bracket, I'd love to hear them. Perfectly happy to go with 2nd hand to ease up on the wallet. Thanks!
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Hi Houseofhits, I'm in the process of tri-amping my system with Crown XTi-2's and, odd as it might seem to many (even me), am finding them to be surprisingly good for my audiophile purposes! Of course, I've had to be careful about it. I most definitely could not use the speaker connectors and had to make a hard-wire bypass for them (not too terribly difficult). There just was simply no detail thru the stock connectors. I also already have in place the benefit of around 10 grand's worth of electronic noise reduction (Alan Maher Designs) which goes a long way for system performance in all sonic aspects - amps included. These amps are only fairly flat (don't measure as good as their bigger brothers), yet are proving to me to be excellent all-arounders. But, their main draw for me is that they have a suite of pro tools that include digital time delay, crossover slopes & freq, EQ and gain (replacing a Ton of passive parts, which helps the sound). Thanks to the analog XLR outs, multi-amping requires no additional expenditures, except for active crossovers or anything. And if you have a digital source that can also act as a preamp, then you can drive the amps directly (although XLR only). But, I'm enough of a tweak to go ahead and bypass my passive crossovers and hear what my speakers can do, direct drive. This is how I think these amps should be used - not just based on how they perform alone, but on how they can be leveraged toward even better system sound. And besides, I can kiss the whole passive crossover upgrade chase goodbye and that's letting me leverage toward reduced system costs, as well. In my case, my stand speakers (Wavetouch Grand Tetons) are already pretty sensitive at 94dB, so a pair of XTi 1002's are all that's needed for them...after some looking around - $410 each on ebay...brand new! Haven't decided yet on which one for my subs.

I can only think of only 2 possible problems with sonics, and even they are rather slight. The first is timbre - this is not the highest-end 'you-just-want-to-crawl-inside-it, live-there-forever-and-never-leave-to-brave-the-world-again'-level of timbre, but nevertheless it is still very good...good enough for it not be an issue for me. But, I am using all that power conditioning and that may be helping with that part at least somewhat, if only indirectly (that stuff usually helps out more with things like soundstaging, harmonics, bandwidth, color, textures, etc, but not directly so much with timbre).

The other issue is subjective speed. I've owned some relatively inexpensive vintage Luxman gear that seemed slightly slower than these Crowns, but the Crowns seem to do fine on their own. But, for me, the removable horns on the Grand Tetons actually improve system speed, yes, even the sound produced upstream, so for me this no issue at all...and I'm not entirely convinced it otherwise would be for me, really, but I have the horns, so I prefer them.

The XTi-2's are so affordable that you can buy one new, play around with the connectors, if you like, and, if you didn't like it, you could sell it as used for not that much less...(Crazy Moe's usually has them (new) on sale on ebay for about the going rate is used). May even help you assess what a Macrotech might be like, if nothing else. But, I suspect you might find the sound as appealing as I do. Hope this helps.

Regards, John
I have several QSC amps and have a few Macrotech 2400 amps, I often see people list things regarding technical aspects of amplifiers, and making statements of this has such a better response time etc, and basically state that the QSC amps are lighter than the Macrotech amps and can match them for sound quality! that is rubbish! I have been trying to find replacement amps for the Macrotech's for years, I have tried every QSC, Dynacord, etc and have been very dissapointed by all!! the difference is amazing! the quality of the sound from a Macrotech cannot be matched by any QSC amp! however the compromise is the weight! but the QSC is nowhere near the quality sound of a Macrotech!!
bryston pro amps....very similar to the consumer amps! matter of fact, pretty much the same, haha. and you get a better price via a pro audio dealer then a high end one!
Yes, I am one of those who has gone through the journey of finding satisfying sound quality and currently use commercial amplifiers. I started with ordinary Sony speakers and then moved to Jamo, then Quad ESL,  and then to Tannoy 12 inch, then Tannoy 15 inch, and currently on Function One. I am very keen to try the new direct AES/EBU input Genelec. That is on the speaker side. I also started off with Sony amplifier, then to Marantz, then to Quad, and compared some vintage valve amplifiers and then Chinese valve amps, then Musical Fidelity, Sudden, and tried commercial amplifiers like Crown, Nexo, QSC, Powersoft, MC2, Full Fat Audio, Lab G., etc. I found that commercial amplifiers can be retrofitted with slower fans to reduce fan noise in quieter home setups. Most commercial amplifiers do not heat up much at all during domestic use. Especially class D designs. I particularly like the sound of MC2 amplifiers in mid and high. FFA is fantastic for bass. Powersoft is an allrounder and convenient with onboard sound card, as you can then use digital AES signal further reducing noise. Lab Gruppen sounds very involving and has a great sound too. The overall sound is slightly different in QSC and Crown with a slightly bright feel. I know that there are many others that I have not tried in detail. Similarly, I find the sound cards like Lynx, Apogee, UA, XTA, etc, all give far better results than upgrading the CD player etc. There is a lot of b*** s*** being pedalled around in the consumer audio sector. There is some, but at least 85% less b s in the commercial audio sector. That, to me is the biggest benefit of moving to the commercial audio gear for home entertainment.  I do not find the commercial solution more expensive than a Naim "Hi Fi" set up, for example. My current set up is computer >AES cable to > XTA 446 > MC2 e45 and e25 > F88 speakers + 15"subs. I recently went to a cinema and found the cinema sound system so appalling that I had to come out. I have visited several hi fi shops and found the sound they sell for a lot of money to be a joke. Some of the very biggest names in home audio sound silly compared to a a stereo pair of commercial Beyma speakers driven by a  Lab Gruppen or a MC2. Period!!
QSC amps and other pro power amps can sound great, although I only use 'em for pro audio gigs (don't like amp fans running in quiet listening or recording rooms). Certainly "bang for the buck" applies with this stuff (I use a "little" QSC amp here and there that's only 375 watts or something per side and will blast along at 4 ohms all day), and I'm not going to drag my groovy living room stereo tube amp around in a road case (although I've never hesitated to drag tube guitar amps around for several decades, so there's that). Note I was recently reading an audio magazine and saw a pic from the Magico factory with a QSC power amp sitting there…wonder what they were using it for?…hmmm…If you need a ballsy home theater amp or anything less delicate than audiophile amps, you can run pro amps at a fraction of the cost of precious "high end" gear…you lose some audio geek cred but so what?
Let me debunk most of the responses. I just bought a Crown K1 amplifier. It sounds as good, as ANY Krell, Audio Research, B&K, Adcom, Muse, Luxman, Hafler amps that I have owned. And it has power reserves in spades. I ran this amp fairly hard for almost 2 hours, and not one time did it ever even get warm. With 350 wpc into 8 ohms, and 550 wpc into 4 ohms, this thing never breaks a sweat. I have the K1 partnered with a Denon AVR 3805 as a 2 channel pre-amplifier. The highs are there, the mid range is there, and the bass is incredible. Transparency is very good. Highly recommended. 
No doubt I'm a little biased as I currently have a Crown XLS2000 for sale, but here are my observations after 4 years of use:

-  massive soundstage, very wide but only moderately deep
-  very powerful low end
-  top end is not sibilant but also not silky smooth...pretty revealing
-  complex passages are done well but not as well as a multi$$$$ amp
-  stable at 2 ohms
-  absolutely silent, black backgrounds and fan never comes on
-  tons of power...1050 watts at 2 ohms per channel
-  gain controls...fantastic way to match to the source so that the source volume isn't maxed out at 9 o'clock, great way to match to a subwoofer preamp out so that the sub gain doesn't have to be turned to 4 o'clock and great way to match left right main volume without a balance control
-  Reliability
-  Absolutely never thumps my loudspeakers when turning on/off or when my preamp or source turn on/off
-  Relatively inexpensive @ $500 new

Yes, I think in certain systems, in certain rooms, with certain sources, you may prefer a $1000 Halo (or something similar) but in addition to the price, you are giving some things up.

Maybe its not someone's cup of tea for their main system, but I suspect they would be pretty happy on a value/sound benchmark to use pro audio in their secondary system.

(and why am I selling it if its so good?....easy answer, its fun to try different things and there is only so much space in the house)
In my studio area with the piles of bass and guitar amps and a synth, I use an ancient (relatively) Alesis RA 100 (no fans, just large heatsinks) amp powering a pair of Mackie 10" 2 way C200 P.A. speakers on stands, with a 500 watt HR120 (discontinued, bought it lightly used for about 150 bucks) 92 lb. sub (flat to 19hz). The Alesis has big level control knobs on the front, and I mix things (keyboards, drum machine, recording interface, with the sub through a monitor fader) through a small Mackie mixer. The Alesis is a bullet proof 100 watt workhorse that never fails. You can buy these things for almost nothing…even the later versions with balanced inputs.  Note that the QSC I noticed at Magico was the same model as mine…a GX3 that retails for around 300 bucks or less.
See here for a serious test of the 2x350 watt Yamaha P3500s:
I recently bought the 2x250 watt P2500s for my son, and it is as good as any high end amplifier, with more power than most, and far cheaper (I paid 300 euros, or about $350).
These both have variable speed fans that will not ever come on at domestic levels. And, of course, they are built like a tank.

I have had experience with Crown amps of both Class AB and Class I (modified Class D) variety.  The Crown pro amps are very nice, but they are built to be able to push a lot of watts and be very durable.  The CTS600, which was a Class AB amp, was very good, but it sounded somewhat dry.  The CTS200, which was Class I and an evolution of the original Crown K2 amp, sounded good and has good bass strength, but had tube-like overtones in the sonic signature.

In both cases, my Channel Island D200 Class D amps and Emotiva monoblocks were significant improvements in sound quality.

Pro amps have their place is live audio and abusive environments, but I don't think they will ever take the place of true audiophile amplifiers.

I use thousands of watts in a live show, 12 single ended tube amp watts per side for my hifi rig (well…not counting my subs).
Count me among those who use both pro and consumer amps. In my office 2 channel rig I have a cheap Crown whatever (A/B topology) driving a pair of LS50's, and couldn't be happier with the sound. In fact, to prove a point at my local hifi shop, I brought that amp in for a shootout between it and the new Anthem STR integrated, which is what, $4000 or so? We both concluded that there MIGHT be a difference, but certainly not one that reconciles the nearly 20x cost difference.

In my experience with home theater, the biggest difference between pro and consumer amps is that the latter are a bit trickier to integrate with a consumer setup. The gain staging is different, the connectors are all different, triggering is different, etc. I actually use both consumer and pro amps in my HT rig, with a Halo A31 powering the front three, and another cheap Crown whatever (I bought the two of them from some guy for $300 total) for the surrounds. I run everything XLR from my Anthem processor, but I still have to go around to my rack, which is in an adjacent room, to turn on the Crown. I've been considering getting a triggered outlet to plug it in to.