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)?
syswei
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 mistake...you 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!

Bill
Shardorne,

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.