I found this on the Marantz M-CR603 receiver/cd player. I'm not sure what the difference is between rated and effective output is, but isn't 10% harmonic distortion a little much, or is this normal?

Rated output
(1 kHz, total harmonic distortion 0.7 %, 8 Ohms) 40 W + 40 W
(1 kHz, total harmonic distortion 0.7 %, 6 Ohms) 50 W + 50 W

Effective maximum output
(1 kHz, total harmonic distortion 10 %, 8 Ohms) 50 W + 50 W
(1 kHz, total harmonic distortion 10 %, 6 Ohms) 60 W + 60 W

https://docs.google.com/spreadsheet/ccc?...amp;usp=sharing