New Digital Switching Amplifiers

Yup, IMHO don't you believe it when they say digital amps can filter out the HF switching noise. Also the PS Audio was very sensitive to line conditions and I had to remove my surge protector.

How do you define "filter out the HF switching noise"?

Just curious.

Ar_t my question exactly. From the tone of your question I'm guessing you have something else on your mind :-).

If you get Stereophile, check out Aug 2005 page 114 for Channel Islands D-100 specs:
"But you can see from this graph how the ultrasonic output rolls off presumably due to the low-pass filter necessary to minimize the H-F noise produced by the switching output stage.
Even so, a relatively high level of this noise is still present in the D-100's output as can be seen in fig 2."

Cdc, lest anyone get an incomplete picture of the D-100's ultrasonic noise test measurements from your quote of the Aug. 2005 Stereophile review of the D-100, here is a quote from John Atkinson's follow up in the September 2005 issue of Stereophile in which he tested current production D-100 amps as resubmitted by CI Audio:

Whereas the original sample had started out cold with about 0.05% THD+noise (including the ultrasonic spuriae), this increasing to 0.1% after an hour, the new sample began at 0.027% and increased only very slightly, to 0.0285%: a promising beginning.