after numerous demos of various components over the past year, I can't say that I ever noticed a difference in sound quality between a 2 channel amp and a 5 channel amp used for only 2 channel. I certainly heard differences in sound quality between different amplifiers, but that differences heard between different amplifiers also depends on what your using as a pre-pro. B&K makes a great product for the money, and I demoed a B&K stereo pre-amp & B&K 125.2 amp, which I eventually returned, after comparing the B&K amp to a demo krell kav-2250, which I purchased. for comparison, both amps were used w/ am avm 20 pre-pro, and the krell made a noticeable sonic improvement in clarity, detail and obviously power. however i was shopping a couple of days ago and heard the same B&K set up with the new paradigm flagship towers and it sounded fantastic.
after months of demos and experimentation, my advice when buying any component is to demo at home before purchasing, or at a minimum get the store to set up whatever your looking to purchase with as close to your speakers and components as possible, but this is a far distant second to a home demo. certain components just don't sound that good when paired together, or perhaps better put, certain components when paired together don't make a sonic improvement which justify what you paid for the new component. for example, a cary cinema 6 pre-pro and cinema 5 amp sounded fantastic paired together, but the same amp with my denon 2805 receiver was not much of an improvement, and certainly not enough of an improvement to justify the cary amp $5000 msrp. however a krell showcase 5 when paired w/ the 2805 sounded fantastic.
when i purchased the krell kav-2250, i was not necessarily looking for a 2 channel amp, but got such a good price on it that i could not pass it up. the krell paired w/ the avm 20 was as good as a combo for music as i have heard at home, and i have now ordered a avm 30 (400 less & several upgrades over the avm 20) which i am anxiously awaiting the arrival of.
another option for a 3 channel amp is the cary cinema 3 (3x200). the cinema 2 is one of stereophile's 2005 recommended components, and the cinema 5 has received alot of awards as well. i loved the cary cinema 5 amp i had for several lenghty demos, but always had a hum w/ it that i could not get rid of. after talking to cary, it was there opinion that it was specific to that particular demo unit, and they wanted it returned to the factory, so i didn't buy it. i eventually need to buy another amp, and am still considering buying a cary amp as one of the possibilities.
my best advice is to do some home demos and listen for yourself, and then you can make an informed purchasing decision.
