Originally Posted by adanny
this logic often comes up. must confess I have never heard the pro amps outside of concerts. i think there are several camps in this argument - some believe that you never need amp-age more than 100 or 200 w. For my speakers in my house, i am not in that camp. I have discussed it with numerous speaker and amp makers, and on several threads here. I feel that is too simplistic a camp.
When you consider that power supply requirements are met in a linear function, and amplitude in an exponential function, it becomes immediately apparent that even a modest amount of dynamic range can use up massive amounts of power. I'd go so far as to say that there's no such thing as "too much power" capability, bearing in mind that the sheer economics of delivering that power will be the deciding factor 99.999% of the time.
some believe it is impossible, or very difficult, to tell one amp from another. I agree it is very, very difficult to tell one SS amp from another but i think impossible is too strong a word. of course, this topic has been debated ad nauseam here. My personal conclusion is that its in fact very difficult to tell SS amps apart at low to mid volumes with low resolution/less-revealing speakers. but at higher volumes, I can start to tell apart the "bass thump" and clarity. tough to determine whether that is because of clipping at transient volumes or some other reason
If you strip out the weasel words and reverse the perspective, that will be much more informative IMHO.
There is a camp that insists that some amplifiers sound "better" (a weasel word that we'll have to put up with for now) and cite vague and hard to follow theories as to why that's "a fact". Trying to pin a member of this camp on specifics appears to be impossible by design. I suspect that they do that on purpose. About the only time I witnessed a member of this camp put it on paper and publish it with his name as author was when the late Harvey Rosenberg of New York Audio Labs fame.
Harvey argued that discrete transistors sounded better than op-amps, and that thermionic valves (vacuum tubes) sounded better than transistors. It was clear, to the point and a complete and total straw man argument.
What Harvey had done was to make a bulletproof case for the relative deficiencies of the three basic audio amplifier modes at the time (A, AB and C) when they were operated outside of their linear range
. So while Harvey got his technical facts straight, he completely failed to prove his assertion. And he completely ignored the possibility that an engineer might design a circuit to operate within its linear range, as was customary even back then. Otherwise the book was a very useful handbook summary of amplifier design. I really mean that. As long as you took the glaring errors into account, it was actually quite informative.
I met Harvey and read his book around the time that Bob Carver of Phase Linear fame was promoting his new self-named company with a challenge to the staff of Stereophile magazine to tell the difference between a couple of highly regarded high-end amplifiers and his amplifier which was tuned to mimic the transfer function of the others. And sure enough, the golden-eared Stereophile writers lost the challenge, completely on their own terms.
My linear circuits professor scoffed at the stunt, noting that if you design an amplifier with a simple unity transfer function, that the amplifier would "have no sound at all" meaning that it acted like the proverbial straight wire with gain. Finding the components that remained perfect long enough to make a practical amplifier was a physical impossibility. And the methods used to force more linearity out of a circuit presented their own complications. And then there was the complex load of the loudspeaker and interactions that certainly affected the loudspeaker's transfer function, if not the amplifier's!
After stepping out of the academic and back into the pragmatic realm, I knew enough to see that an amplifier made from unobtanium, moon rocks and virgins' tears was indistinguishable from an amp made from tinsel and squirrel teeth as long as care was taken to keep inside the linear envelope. I also learned the dirty not-so-little secret of loudspeakers, namely that their distortion on the best of days far exceeded the sum total of the entire signal path ahead of them on the worst of days.
there is another camp that believes that commercial amps at 1/10th the cost are the same performance and sound quality as MBL, Pass Lab or Marl Levinson kind of amps. I am intrigued by this logic but the arc-welder nature and fan noise has kept me away. One of these days, if i can find a 1000W commercial amp that doesnt have high fan noise, i might buy it just to test it
Bob Carver did win, after all.
I'm not sure what all the talk of fan noise is about. Plenty of commercial products don't have fans, and plenty of home-made ones do. I think that someone told you a fib, both about the fans and the notion that high-end stuff being knitted by nice old ladies with only your best interests in mind. If that was true, they wouldn't be taking 1000% or more profit margins!