Big Injun Chief has a few. He also has knowledge concerning the fan noise (and how to eliminate it) for pro amps.
Unfortunately, you find this in nearly every aspect of marketing, especially technical areas. It's like digital camera megapixel wars, where they don't mention the noise introduced by denser sensors. I guess we have to take it upon ourselves to have some understanding of the specs, and know to compare the same spec from product to product.
I suspect that the Onkyo, like our Yamahas, has 7 discrete amplifiers. The bottleneck is probably the power supply.
The power supplies are indeed the choke point. Higher end AVRs have multiple transformers for video and audio sections, giving closer to the rated power output. Most AVRs and amps also have a wider range than is in the specs. The NR3009 is rated at:
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
However, the Wide Range Amplifier Technology (which are inverted Darlington amps) have a bandwidth of 5 - 100K Hz.
They do have discrete amplifiers for each channel. The NR3009's power supply is rated at 1160 watts power draw from the wall. You will get a max of about 70 percent of that to power all of the video and audio circuitry and amplifier stages. I'm not doing the RMS math with 9 channels driven. Bottom line is tht you get less than the stated power with more than two channels driven. The NR5009 comes much closer to the stated specs due to the massive toroidal transformer in the power supply. With class AB amps, the heavier is actually better...
Edited by climber07 - 5/2/13 at 1:42pm