Musical Fidelity is also pushing that you need mega-watts that are faithful to the music. And Sam still loves his 2.5 watt S.E.T. QSC is what it is, sound reinforcement gear. Cheap watts never quite seem to cut it.

PA amps are robust, powerful and reliable. They do their designed job wonderfully. However, they tend to sound quite "crispy". If you recall the sound of Japanese receivers during the spec wars of the 70's you already know the sound.

Some have found they like the sound however and are pleased with it. It's worth a try if it intrigues you. The amps are readily available to rent and upon approval in many locales and by mail order.

Years ago - long before Antony Michaelson began touting beefy amplification - a friend of mine put a big Crown amp into what had been a really fine sounding system. He had 4 ohm speakers, liked big band jazz, and thought he could benefit from POWER. The Crown didn't last a week. It wouldn't have lasted that long if not for his hopes that burn-in might improve the horrible sound.

Clay,

That was the same take on the Phase Linear 400. Then the 700 came and went. It did have some "big, honkin power meters" that probably distracted the listener from actually hearing the flaws. I must admit it did look very cool!

I always love Mac gear for the same reason, except their equipment is always beyond reproach. It was also beyond my wallet.

There is no substitute for WATTS. Good clean WATTS. You cannot reporduce the sound of LIVE music with miniwatts. To move air it takes speakers with the abilty to drive the air, to drive the speakers it takes WATTS. There is no way a miniwatt 2 watt amplifier is gonna sound real. Don't care if the speakers have an efficiency of 100dB/W...it ain't gonna happen. Crown, QSC, Hafler, and a few other pro names that work with lotsa watts that work. Even McIntosh is now pushing lotsa watts in their large expensive systems. I've seen teh same QSC amps running for over 5 years now, touring under adverse contidtions, and they keep sounding just fine, and they take a beating, up teh stairs down teh stairs, in the truck, boucned around...low priced and they work. StartLand Ballroom in N.J. uses 32,000 watts of CROWN power...cool. They don't get live Leslie West going with 10 watts of overpriced nonsense. Nor Buddy Guy cranking out some great stuff...WATTS sounds great.

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Clay,

That was the same take on the Phase Linear 400. Then the 700 came and went. It did have some "big, honkin power meters" that probably distracted the listener from actually hearing the flaws. I must admit it did look very cool!

I always love Mac gear for the same reason, except their equipment is always beyond reproach. It was also beyond my wallet.

The problem with some people's use of the Phase Linear amp was that they used them for pro sound audio. When run into a 4 Ohm load the 400 would get very hot. Some roadies/live music sound engineers tried to run them into 2 Ohms and they would literally start on fire. Hence, the moniker "Flame Linear." They were not designed for that, and I think when properly reconditioned they make a fine home audio system amp for those who understand their limitations.

This brings up a good point: pro amps are designed to run into difficult loads. Modern Crowns, QSC's, etc. can power 2 ohm loads all day and grin while doing it. These things are tough.

Lab
Gruppen is another fine pro amp, workhorses. Marketing, and who is dismissing Crown, only audio phlakes who think the brands that are hyped as some mystical devices with some kind of magical sound properties. Crown has been around longer than most of teh hi fi brands, bbeen one of the original pioneers in reliable super powered amps. Used where BS doesn't hold up to reality.Where PROS who know what the amp needs to do, and at what price, not paying $10K for some 10 watt usueless junk, hyped into the world of utter nonsense. JBL/Crown combos are making sound in more live arenas lately more than anyone. Under conditions that would probably make most "audiophile" stuff go up in smoke. Crown and QSC are marketed to a different customer, audio nut brands like Chord,Jolida and so many other over priced turds, marketed to the individual who doesn't understand basic electrical designs, but goes for the verbage of mystical perceptions and marketing nonsense. When an arena is full of 5,000 PAYING customers, the promoters sure don't want teh systems crapping out....reliability performance is first on their minds. And yes, the sound matters. Most horrible sounding live events is because of teh dudes in front of teh controls, pumping up the bass, making teh highs a shrill as can be...not teh electronics driving the speakers. Put one of the "boutique" brands into a live event service, let's see just how well made they are. All the magic wiring and other nonsense ain't gonna hold up to reality. Use some of that MapleShadey speaker wire, let's see how long that holds up. How come they don't use cable elevators at live evnts? Why would it matter reproducing the sound but not when producing it? Dow do the electrons know, at which end of the cycle they are at?

Providing power to huge banks of speakers to fill large venues is quite a bit different than providing power to a single pair of speakers in the room of a house. Pro amps are not even rated to provide clean power. For my system where I'm 10 feet from the speakers I'd rather have an amp that is documented to have ample power within the audible audio spectrum with low distortion. Pro amps are documented to provide a lot of power into low impedance at a single frequency with 4 to 100 times more distortion. If anything even if rated the same the pro amp will not have anywhere near the power they are claimed to have.

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Still begs the question.

If Mark Levinson is basically built on the same lines as JBL pro amps and If Crown and QSC have such great knowledge why are they quickly dismissed as hifi amps ? What is the difference

I'm not quite sure what else you want.

"Mark Levinson is basically built on the same lines as JBL pro amps".

No, this isn't true other than in the most basic sense that they are both amplifiers and are solid state.

PA sound reinforcement amps are built differently using circuit topologies which are designed to be efficient, robust, inexpensive. They typically employ a lot of negative feedback to make them ultra stable under any load. The tolerance of parts - such as resistors etc. - are quite broad, etc. They are not designed to reproduce subtleties, rather they are designed to handle a heavy load and to do so all day and night. They are beautifully and wonderfully designed to accomplish their purpose.

As a result, PA amps sound very different from high end amps. Think heavy pickup truck v. Ferrari. Both do their jobs exceedingly well but they are not interchangeable vehicles even though the basics are the same (engine, wheels, internal combustion, steering wheel, a transmission, drive on roads . . .).

DUP is correct in stating that Pro amps are capable of withstanding lots of abuse. Some high amps would indeed overheat or otherwise panic under these conditions. Other high ends amps would do great but would not be cost efficient in this environment. He is also correct that there is no excuse for bad live sound. While there are bad sound systems out there, most bad sound is a result of a bad set of ears running the sound board.

An additional thought: If you like the sound of loud amplified music in clubs and other live venues (as DUP has told us he does) you may be very pleased with the sound of PA amps at home. You will get the same type of sound at relatively little cost. Those of us that listen to acoustic music are generally not pleased with the sound of PA amps as the do not do well reproducing this type of music. They do not have the accuracy of timbre, the ability to sort out complex sounds (such as in a full orchestra), do not handle delicate decays and ambience well, etc.

Again, there is absolutely nothing wrong with using a pro amp if you like the sound. Like speakers, amps sound different and one should pick the sound that appeals to you.

You may find illustrative the fact that mastering studios do not use Crown, QSC and similar PA amps. They use amps that have the ability to express nuance - many studios use high end enthusiast amps that we would all recognize.

Acoustic sounds for teh crowds, done with theose horrible "PA" amps.....QSC, inexpensive, robust, and sound fine for the nuances and acoustic "timbre" etc etc...running on non audiophile 240V, unheard of!!!!! How dare they do live music with such stuff!!!! http://prosoundnews.com/articles/article_5180.shtml