More power "better"

I am currently running a pair of Proac Response 1.5's with Classe 5 pre/70 power. They seem to play well and sound good, but I was told that more power would "open them up" and provide more control. I am also wondering at how much power is reasonable and not wasted. I would like to find some older Classe amps with more output but I am also wondering if an amplifier running "pure"class A would sound more powerfull. For example Krell KSA50s as compared to my Classe 70. Tubes also come to mind, but I think that new solid state is damn close if not better(certainly more reliable).If I were to go tube, I'd probably look at VTL MB125's (can't afford the big stuff). Any suggestions would be greatly appreciated esp. by those who currently own Proac.
i don't own proac and i do use tube amps. i have a pair of very effiecent speakers (jm labs mezzo utopias) that can run on anything from 50-200 watts. when i first bought them, i ran them through a 45-50 watt tube amp (cj's mv55). they sounded great. shortly thereafter, i replaced the amp with cj's permier 12 monoblocks wich produce about 140 watts per channel. the difference was, as many audiogon audiophiles would expect, incredible. better bottom end (the increased power helped the woofers move in and out more completely and accurately) and sharper detail through out. some of the improvements can probably be chalked up to the amp itself, however, i wholeheartedly beleive that the added power enabled my speakers to perform better. in terms of how much power, what is the manufacturer's suggested range, what type of music do you listen to and at what volumes? i think a safe (and hopefully affordable) bet would be to try and buy an amp (or amps) that deliver enough power to put you right in the middle or 60-65% range of proac's suggested range. although i own cj, i very much like some of vtl and ar's offerings. in my experience, today's tube amps are pretty reliable. they may or may not be for you, but don't cross them off your list without listening--don't worry about their reliability. like anything else, if you buy quality you should be okay. all of that said, be mindful of the fact that searching out and purchasing nos tubes is a fun, but expensive, habbit. good luck.
Alun...I had a similar experience. I bought a pair of Proac Studio 150's and felt my Arcam 9/9P pre/power combo (70 watts per channel)wasn't getting the best out of them. I consulted my local dealer and he recommended a class A amp....a Sugden A21a...I must admit I was sceptical that this single 25 watts per channel amp would easily replace two amps bi-amping at 70 watts per channel. I was wrong and a home demo proved that the theory behind Class A to me....(see other threads for the details of why this is so)....anyway I got more control,more detail and a clearer sound at exactly the same price as my Arcam combo (£900)-traded those guys in and the Sugden now happily drives my Proacs. I would recommend searching out a Class A amp(s) of your choice and trying a home demo before buying..... Regards, Ben
hi alun,

i tink class-a amps *do* sound more powerful than comparably-rated non-class-a amps - prolly because they put out more current. the proacs would definitely like more power, tho what ya got should be sufficient in a smaller room.

the least expensive way for you to increase the power would be to get another matching classe amp & bi-wire - put the biggest amp on the mid-woofs of the proac; or if ya got another classe 70, ewe could try biamping vertically.

proac uses the audio research ls-16 & ls-25 preamp w/the a-r 100.2 amps, fwiw....


ps - i have an electrocompaniet aw100 amp f/s on audiogon - class-a, 100wpc into 8 ohms, 190 into 4 ohm, >80amps current output... :>)

After 30 years of building both home and studio playback systems, I have concluded this. The way to approach the reproduction of sonic realism is by having tons of power at your disposal. I'll use my own system as an example, but this is how I set-up studio monitoring systems in the Hollywood area and high-end home theater systems too. I am currently running a three-way low-level crossover system (tri-amplified). Each of the six woofers has its own 400 Watt amplifier (speaker-fused at 150 Watts). Each large midrange is driven by a 400 Watt amplifier (spk-fused at 75 Watts). Each tweeter is powered by a 250 Watt amplifier (spk-fused at 25 Watts). All amplifiers are Bryston models and the crossovers are Bryston too. This may seem like over-kill power, but the resulting sound says it all. Two audible things result. First because the Brystons are generally operating in the bottom 10% of their power range, the distortion and frequency response is clean and flat. Second, when realistic peaks are required of the amplifier, these powerful units have no problem providing steep peaks instantly, meanwhile the speakers are protected from heat burn-out by the fuses. I have never lost a driver unit using this method -- lost a few fuses along the way, but no speakers. The big advantage is the realistic dynamic range this system provides. It's not about being able to play it loud, although it certainly can be, it's about having the effortless ability to reach those peaks when demended of the source material. A drum, cymbal crash, bell clang, are obvious examples of going from zero power to max power in nanoseconds. This translates into realism. Of course this system is adjusted and measures in-the-room within one dB from 25Hz out to 20k and has inadable noise even a full volume -- that goes without saying these days. But, no matter how good a fidelity a system has, if it does not have power and lots of it, it sounds compressed to me. Think of it this way, suppose you have a 125 Horsepower/2000 pound car going down the highway at 50 mph and you want to pass someone. You can certainly pass them without problems. No suppose you have a 850 Housepower/2000 pound car going at 50 mph. Do you not believe the second car would pass with very little effort as compaired to the first car? Of course. What is really going on is the amplifier is trying to control the speaker cone so as to make the cone the mechanical equivilent to the electrical signal provided by the source. A strong ampllifier will control the speaker cone with little strain whereas the smaller amp will strain to control the cone. This is heard as "amplitude compression" and the ear is very sensitive to compression of peaks. I can alway be certain the first comment people make when hearing one of my monitor designs or my current home system is "it sounds so real, so immediate." The immediate sound they notice is the fact that (even with the fuse) the midrange (for example) is under complete control by the amplifier at all times. By measurement, the fuse will let peaks of 200 watts go to the speaker (which is rated at 50 watts) for short periods of time -- the initial peak. Those peakes are usually so short that little heat is produced, but the impact of the wave front from the speaker is there to hear. It's like being held and shaken by a 10 year old child compared to being held and shaken by a 300 pound body-builder. Both can shake you, but one is definately going to put your body where they want it. Power = Control = Realism. ~HAPPY LISTENING, Steve Desper