New Digital Switching Amplifiers


Anyone had the luxury of comparing any of these fine digital switching amplifiers to eachother or to other high end amplifiers such as Pass, Krell etc?

Nuforce
Channel Islands Audio
PS Audio GCA
tpk123
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.
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.
I'm glad we could bring back this thread which was on its way to oblivion because it is an interesting topic.
Ar_t, maybe I didn't understand your question. I was refering to filtering the HF switching noise the amp itself produces.
Tvad, even the original distortion specs you mention are ridiculously low and probably people wonder how can audiophiles argue over such tiny changes in distortion. The actual printed graphs in Fig 2 however look a lot worse than numbers on a page.
Probably the worst Pioneer receiver is 75% accurate and the best Halcro is 90% accurate so any differences are small on an absolute scale. Nothing is perfectly accurate and you make a choice based on 1) your overall system, 2) preferences, and 3) what you find objectionable.
So if tpk123 is making a buying decision, then the objective is to weed out "bad" products, however small the differences, and buy the right product based on 1), 2), 3).
When I had the PS Audio, it gave me headaches like when I listen to CD's from the Cranberries. Could've been my system, room, CD's, or ears, but it didn't sound as good as "analog" S.S. amps IMS.
Even if they can filter out the HF noise, I'd rather not have a filter used at all. One more component in the chain to mess up the sound.