Garbz stated:
"Duc with upsampling you really have to wonder why? There's really no great benefit to doing so. With 8x oversampling in DAC chips the first reflection of the audio data is already beyond 350khz, pushing it any higher is useless. As for detail, upsampling can't add what isn't there. Infact most of the time seeing how upsampling doesn't always change the sampling rate with flat multiples, the result can be worse."
I agree. This seems very reasonable.
I, too, am interested in the 640C v2 and 840C. In fact, just last night I started to seriously consider the questions being discussed in this thread. I think I will end up going with the 640C v2, as the upsampling does not appeal to me (especially at the price points of upsampling players). The real question (or final question) for me, though, is: will the 640C v2 beat my CD25.2? I tend to think this may be a "tight race," and thus some further insight would be nice (especially before I make a purchase).