Originally Posted by deeda
Are these numbers an apples to apples comparison. If all channels are driven for the Denon, Marantz and Parasound units, will they result in the 150, 140 and 125 watt amounts noted or will they result in a much lower number?
Manufactures rate their products in a variety of different ways. For example, you'll see these variations on 100wpc:
All channels driven, 1khz
All channels driven, 20hz-20khz
One channel driven, 1khz
One channel driven, 20-20khz
All channels driven, at x% THD
One channel driven at X% THD
For example, look at this review for a mid-range Onkyo Reciever:
Note it's a multi channel reciever, but the amp is rated 80watts into only two channels. When tested, here's how it's amplifier compares:
"Two channels driven continuously into 8-ohm loads:
0.1% distortion at 75.8 watts
1% distortion at 105.0 watts
Five channels driven continuously into 8-ohm loads:
0.1% distortion at 53.1 watts
1% distortion at 66.7 watts"
Because of these variations, it's best to take WPC claims with a grain of salt.