Don't tell Pmbuko.

This would have been a good double blind test to do at the Axiom plant last month....an "off the shelf" 100 watt receiver vs an Uberexpensivestein Mach 2 amp running the same speakers.

+1 to what wheelz is saying.

When I had older Yamaha 5 chanell amp, adding an Emotiva UPA-2 amp made a startling difference with my then Energy Speakers.
Most multi channel amplifier measure WATT output power by the stereo.

Two Pioneer Elite AVR example specs.

VSX23THX
Front (stereo) 110 W + 110 W
Power output (1 kHz, 6 Ω, 0.05 %, 1 ch driven)
150 W per channel
Guaranteed speaker impedance 16 Ω to 8 Ω,
less than 8 Ω to 6 Ω (setting required)

SC-05
Multi channel simultaneous power output (1 kHz, 1 %, 8 Ω)
7ch total 700 W (SC-07)/630 W (SC-05)
Continuous Power Output (20 Hz to 20 kHz, 8 Ω, 0.09 %)
Front 140 W + 140 W
Center 140 W
Surround 140 W + 140 W
Surround back 140 W + 140 W
Continuous Power Output (1 kHz, 6 Ω, 1.0 %)
Front 180 W + 180 W
Center 180 W
Surround 180 W + 180 W
Surround back 180 W + 180 W
Total harmonic distortion 0.05 %
(20 Hz to 20 kHz, 130 W, 8 Ω)

SC-05 is continuous power. I love it, my M22, M2 and QS8 are unreal on the SC-05 (which I upgraded to from the VSX23THX).

Never heard of that guy .

No, as I said at low volumes the bass was what I could easily notice, but at normal levels there is a difference, the bass as mentioned but the vocals and instruments seemed to have better seperation, more detail and at high volume levels the music is just crystal clear, no distortion until I went well beyond anything anyone would try to listen to. I think I had the SPL meter at 105-110db and still pretty clean sounding.

It still comes down to diminishing returns, is the ~$4000 of the A1400-8 or ~$2500 of the A1400-2 worth the costs for this better sound. For some it is for others not so much. I still don't own one, maybe someday.

Thanks for the clarification. I read the subtle difference in bass at low volumes and the more dramatic difference at loud volumes but was curious about the "in between" or normal to moderately loud listening volumes. I definitely would like to own a separate amp someday but there are a lot of other things I need to put my money toward first.

External amplification can have benefits. It depends on a lot of factors the extent of its benefits, in some cases it could be none at all. Such factors as room size, listening distance, SPL levels, sensitivity, impedance curves most notably the dips all can play important roles if a more robust amplifier with more dynamic headroom is needed.

A great example of the need for external amplification is this thread right here.

http://www.axiomaudio.com/boards/ubbthreads.php?ubb=showflat&Number=326093&page=1


The OP noted "harshness" during loud/dynamic passages. In these instances those brief dynamic passages are creating audible distortion. In this case the receiver does not have enough headroom to reproduce those peaks without distortion. Moving up to a more robust external amp with more dynamic headroom and lower distortion will certainly have audible improvements in perceived sound quality.

Bill, you've in part misinterpreted the Pioneer specs and amplifier power ratings in general. All amplifiers sold in the U.S.(and effectively, Canada as well)have to comply with FTC(Federal Trade Commission)regulations in issuing a power rating for the units. In relevant part, it's required that FTC ratings be at the full rated power for at least five continuous minutes. Both of the Pioneer units that you mention are in compliance. They meet exactly the same continuous power standard, with the VSX23 being rated at 110 watts per channel and the SC-05 140 watts per channel. The difference between 110 watts and 140 watts is 1dB of maximum output. For example, a brief split second peak in very dynamic material could be played at 105dB using 110 watts and 106dB using 140 watts. That's all.

It can also be pointed out that this isn't, as an earlier reply characterized it, merely an individual who "believes" in a "theory". It's a very basic point of audio amplifier technology that power delivered with flat frequency response and inaudibly low noise and distortion(typical of even modest units these days)results in transparent amplification without any added audible coloration to differentiate the units. Enthusiastic and sincere contrary reports are available in abundance, but the only reliable way to determine such matters is by a controlled double blind test. Such tests have failed to show the differences reported in open hearing. When the name plates and price tags disappeared, so did the differences which were previously reported.

Yeah. I don't capitalize my screen name.

So in essence it basically like me trying to lift 200 pounds by myself, I may be able to do it, but not very well, I might jerk, slow down, or drop it, In other words causing distortion in the sound in the form of peaks or clipping. As opposed to 3 or 4 people picking up the same 200 pounds. It can be done simply, smoothly, and without much effort. Basically giving me clean, smooth distortionless sound. So I guess the question becomes at what weight limit can I easily handle without stress. How do you go about finding this limit? When does it become audible?