Originally Posted by Jon S
A larger power supply with sound more open and less strained than a smaller one because it has a larger power reserve which can meet demands which a AVR cannot come close to.. This is what gives separate power amps a noticeable difference in sound.
What does a "strained" sound like? What does "open" sound like?
Stereo Review demonstrated years ago that below their rated output consumer amplifiers are fungible. So I expect we are dealing with the domain of short peaks in program material that could drive an amplifier into higher distortion or clipping. Aa lot of water has gone under that particular bridge and I won't rehash it.
Note that AVRs are generally rated with only two channels driven and separates are rated with ALL channels driven, again due to the power supply differences. Which generally means that the separates should be able to provide more power with only two channels driven...
There have been many posts on this forum about the levels and bandwidth of surround channels. I think the consensus of them is that you are unlikely ever to encounter program material with simultaneous sustained peaks in all channels.
This being true and I accept that it is, there is merit in the industry argument, accepted by the FTC, that power need not be rated for more than two channels simultaneously.
The top line Onkyo's have a larger power supply than most AVR's... For example, a TX-NR906 can provide about 100-120wpc with 5 channels driven. A comparably priced Sony ES receiver will provide only about 35wpc with the same load. That is about 4-5dB less than the Onkyo which is a very noticeable difference in volume altho both are rated about 130wpc
The 906 claims-
A 9.6A power consumption
140 watts minimum continuous power per channel, 8 ohm
loads, 2 channels driven from 20 Hz to 20 kHz, with a
maximum total harmonic distortion of 0.05% (FTC)
The Emotiva-5 specs claim-
1200VA power transformer
200 watts RMS @ 8 ohm (0.1% THD)
Power Band Response 20 Hz to 20 kHz with less than .05db deviation at rated power
But, maybe not. They have link to the tests and it says that power was measured with a1kHz signal low passed at 80Hz. Total Harmonic Distortion is measured at 1kHz, low passed at 80 and high passed at 20kHz. However let's give them the benefit of the doubt
The Emotiva is a class A/B amplifier which means that it is somewhere between 70% and 80% at best. 80% of 1200VA gives 960VA maximum. Ok those big caps store enough energy to deal with short term peaks so the 960 looks reasonable.
The 906 has a 9.6A draw so 80% would be 724 for 7 channels. So compared to the Emotiva the 906 might deliver 100wpc, just as you suggested.
Not so shabby but perhaps not what you need if the goal is 110dB sound on all channels.
But now I will reverse course to say that if the goal is concert hall levels for music or the same peak sound levels of a good theater, the 906 is a tad shy. I have larger and heavier amps on hand, but I really don't try to duplicate a symphonic wind band in my family room (OK once in a while and only if my wife is out) and 99% of the time the 906 does the job.