Originally Posted by penngray
Undistorted sound will sound the same no matter what price tag/label/color or name is on the box!
Sure it will.
But just like various driver/enclosure/crossover designs and configurations can alter the final sound waves that emanate from a pair of speakers, different amplifier components/circuitry can have an (albeit more subtle) effect on the signal that gets relayed to said speakers.
It has been said here that amplifier can realistically only degrade signal quality if it is pushed past reference levels. This, in my opinion, is a moot point. The fact is that more expensive amplifiers can (in general) be pushed to much higher power levels without distorting, which not only allows one to play sources at higher decibel levels, but also experience a fuller dynamic range (which are becoming more and more limited due to the introduction of recordings engineered to be "loud" all the time, and designed to be more "resistant" to compression for playing on digital audio players - but this is whole other topic). In the same vein, more powerful amplifiers enable one to get more out of less efficient speakers.
The problem is that when you increase power, you also increase the potential for signal noise. This is why more expensive amplifiers have more stringent (expensive) capacitors and components such as torroid power supplies (at least in A/B class amps) while cheaper ones do not.
Therefore, the advantage of a more expensive amplifier is mainly signal noise reduction at higher power (ie, microphonics imparted by input capacitors to RF interference from power circuitry which surrounds the signal path). I would agree that the vast majority of modern amplifiers (even the ones in budget AVRs) have undergone enough iterations to make these sources of noise negligible at their reference decibel levels. But not everyone wants to be limited by the reference decibel levels of a budget 50 wpc A/B amplifier.
Then there is the age old question of amplifier class. While all A/B amplifiers may sound similar at reference volumes, what about tubes or T-class amps? In the case of the latter, does the use of a transistor to "sample" and create, what is in effect a digital-like signal produce a different signature than other designs? They supposedly sound more like tube amplifiers - a function of their relatively low current requirements due to their "sampling" technique.
I currently own a run of the mill, recent Denon AVR. I have been wondering for a while whether different amplifier designs could really make a perceptible difference in my music listening. Recently I came across a T-class amplifier that, unlike the low wattage limitations of other models, is rated at 60wpc. As it was reasonably affordable, I decided to order one (Virtue Audio). I can't wait to do some A/B testing between this amp and my Denon...