Since I outlined my measurement methodology in the entry below, here are some recent results found using that methodology (1kHz output only reported).
| Model | Specification | Power output per channel (1kHz continuous) | |||
| 7 | 5 | 2 | 1 | ||
| Denon AVC-11SR | 7 x 125 | 62 | 127 | 156 | 167 |
| Harman Kardon AVR-8500 | 5 x 110 | – | 132 | 159 | 176 |
| Integra DTR-7.4 | 7 x 100 | 93 | 102 | 134 | 148 |
| Integra DTR-8.4 | 7 x 110 | 99 | 116 | 144 | 163 |
| Marantz SR-7400 | 7 x 105 | 82 | 93 | 133 | 152 |
| Rotel RSX-1067 | 7 x 100 | 118 | 127 | 151 | 158 |
| Sony STR-DA5000ES | 7 x 170 | * | 113 | 203 | 209 |
| Sony TA-DA9000ES | 7 x 200 | 134 | 157 | 192 | 192 |
| Yamaha RX-Z9 | 7 x 170 | 123 | 150 | 168 | 182 |
| * The protection circuitry in the Sony STR-DA5000ES receiver operated too aggressively for me to obtain valid results with all seven channels running. | |||||
From the above, it’s clear to see that different brands have different philosophies when it comes to specifying output. Harman Kardon and Rotel are very conservative, and their outputs actually exceed specification with all the channels operating at the same time.
Some kind of standard would be useful here because, the way it is, it’s impossible to compare the quoted specification between brands.
ADDENDUM (Tuesday, 10 August 2004, 10:36 am): I should have made a couple of other points. First, we use 240 volt power here in Australia, so these measurements might not be valid in places like the United States, where 110 volt power is used since, necessarily, similar receivers will use either different transformers, or different windings on the same transformers.
Second, take all my measurements to have an error range of about plus or minus five per cent. The load resistors themselves are only rated to 1% accuracy. The meter is probably less accurate than that, and I have to find the point just before clipping by eye on an oscilliscope. In addition, to derive the power output I have to square the measured RMS voltage, which amplifies considerably any measurement error.
Finally, don’t get too het up about precise power measurements. The difference between 100 and 105 watts is a mere 0.2 decibels!