Read a new review of the Denon 2803 in S&V magazine.It has a 7 X 90 W amp, so they claim, but only outputs 83 W X 5 , and 75 W X 6 according to there lab tests. I can't help but look at my Onkyo and wonder...... I'm convinced seperates are the way to go. If you by a receiver make sure it has preouts. I'm glad mine does.

Here is a very interesting table comparing the manufacturer's specs vs. the actual measured power output. As you see, H/K is the only brand that seems to be consistently honest (blue numbers) with regard to power specs, although other brands (including Denon and Pioneer) have produced amps here and there that significantly outperform their own specs. Some brands (including Sony and Kenwood) are consistently lying about the power.

Very cool link, thank you Sushi.

Though there is only one Rotel product in the list, I'm glad to see it outperformed it's own specs. I had heard that about them and it's one of the reasons I purchased my Rotel gear. Yeah for me!

Hi all,

Actually, the Denon did pretty well. If you want to scrutinize dubious power output claims, check out the June 2003 issue of Sound&Vision--the Onkyo TX-NR900, which claims 110W into 5 channels, produced only 55 watts at clipping into one channel! With five channels driven into 1 kHz, it delivered 52 watts per channel. There's a note that the Onkyo "exhibited thermally-induced current limiting consistent with current EIA standards. . ."

In the same tests, the H/K 7200 delivered 142 watts per channel with all five driven into 8 ohms (it claims just 100W into 7 channels) and the JVC did 121 watts per channel into all five. The JVC and H/K also drove 4-ohm loads with one channel driven (255W and 332 watts into 4 ohms, one channel driven, respectively). The Onkyo delivered 178 watts for 2 to 3 seconds before current limiting engaged.

Regards,

Almost makes you wonder if these companies are using any measurement equipment at all or just basing their specifications on white paper theoretical values.

In fact, Alan's commnets raise an interesting conandrum on receivers' power specs: (1) the real performance limits of the amp / power supply per se, versus (2) how conservative the current/thermal protection has been set for a given receiver. This definitely complicates how you read the power specs of modern receivers.

It would be nice if all these third-party reviews actually measure and distinguish between (1) the max power at the clipping point, and (2) the max power limited by protection circuit, since these two mean very different things for the amp.

Why do they teset out put power at 1 kHz in stead of 20 Hz - 20kHz? I never understood this.

It's the difference between continuous power output and dynamic output. For example, the used Yamaha M80 2 channel amp I just picked up for a song is rated as follows:

Continuous Power Per Channel

20Hz-20KHz 0.003% THD 8 ohms ...... 250 Watts
20Hz-20KHz 0.007% THD 6 ohms ...... 290 Watts
20Hz-20KHz 0.020% THD 2 ohms ...... 330 Watts

Dynamic Power

1 KHz 8/6/4/2 ohms .................. 380/480/640/850

Boy, now I'm really, really glad I didn't buy the Marantz 7200, and opted for the H/K 525. Claimed 105 W x 6, got 27!!

O' course, I don't know how the 525 scored...