Upsampling the way to go? ?

I have also heard there have been some issues with the Perpetual Technologies P1A, and I don't know if it is an ongoing problem or if PT has fixed the problems. In any event, I posted the link purely for informational purposes and not to endorse any particular product--just to be clear. Although PT's implementation of the technology may leave something to be desired(although a friend of mine was quite happy with his P1A and there have been some very favorable reviews of the product as well), the general overview still provides useful insights into the basic components of the upsampling process(i.e. not specific to Perpetual Technologies), which is what I thought would be interesting given the many questions and misconceptions on upsampling that seem to repeatedly appear here.

Tim

Tom: I find your results comparing the Mill II to the DAC 3 pretty interesting. Like you, i was also interested in that piece. I found the Mill II to sound much more "organic" i.e. more musical, natural and fuller sounding. In comparison, the DAC 3 sounded somewhat "bleached", lacking detail and lacked the warmth, body and bottom end extension that the Mill II is capable of. I'm sure that i could've gotten better results with the ARC if i really tinkered with it, but i didn't feel the need. Sean
>

Is it true that the Audio Note has no filtering ??

This could not be good for amplifiers and tweeters.

I thought it was a requirement that the aliasing frequencies must be filtered out of the analog output.

Can anyone comment on this?

As far as I know, an unfiltered DAC's analog output will only affect the speakers negatively if it affects the amp negatively. In other words, it's the amp that will potentially damage the speakers if it is made unstable by the unfiltered ultrasonics. The resulting amp distortion artifacts would cause any speaker damage; the speaker is actually a filter in and of itself, and would not be damaged the ultrasonics alone. Fortunately, I think few amplifiers would be disturbed to this degree, but the possibility always exists (presumably, AN electronics would not be among these).