New Digital Switching Amplifiers

Also forgot to mention the specs were done with a steady 8 ohm simulated load. Real life loading would probably bring out the switching noise even more.
For an interesting read see the paragraph on "The Quest for that Old-time Religion " section:Hammer Dynamics Super 12. Dick Olsher talks about lowering the tweeter's x-over frequency. During *dynamic* passages "while such a solution results in a smoother frequency response, often the sound quality is far WORSE because of increased distortion. That poor tweeter is made to work much harder than it really wants to. In the end, it is reduced to painful screaming".
I'm saying this as an analogy to Stereophile's steady state 8 ohm load of the C-I amp versus real music.
Don't get me wrong, for the price, etc. I'm sure the C-I amp sounds really nice, it's just not perfect.

I understand that my digital amp output has some ultrasonic signal that would not be expected from a linear amp. Last time I checked "ultrasonic" means you can't hear it, but it does keep the bats away. :-)

There are 2 kinds of noise:

One that goes out on the speaker leads at the switching frequency. We'll say in the 500 kHz range. (I believe Tripath and Nuforce may be closer to 1 Mhz.) The other is all the crud in the 60-100 Mhz region that will mess up TV reception ans some other things. Two different issues, 2 different solutions.

As for distortion changing with warm-up:

You can get the distortion to drop if you increase the "stand-by" current drain. Problem is, you run the risk of destroying the switching transistors if you get it too high. There could be a thermal change in that parameter in the unit under review.

So for a 10kHz signal to the speakers, the amp sends out 510 kHz?

No. There is no correlation to the switching frequency and input signal. If you took x number of any brand of "self-oscillating" amps, put them along side, they would all be different. The ones that I use will vary between 480 kHz to 510 kHz or so at idle.

The old style ones.......the ones that gave "digital" amps a bad name......used a fixed frequency oscillator. It remained constant.