Phil Leigh;692199 Wrote: > So John, are you saying that on 44.1 material you prefer a NOS with a > good analogue filter set for 22Khz vs an ASRC DAC running internally at > 384 or 768 with an appropriate digital filter? > > Just curious. > > That "dirt" you refer to is exactly what I don't like about all of the > NOS DAC's I've heard. Of course this doesn't mean ALL NOS DAC's are > empirically bad... simply that I personally haven't heard what I > consider to be a good one. > > Interesting about the heat phenomena. The heat must be causing the > Johnson noise to rise inside the DAC, no:? - maybe the noise is having > a "dithering" effect? > regards > Phil
My preference is a DAC which uses properly implemented digital filters, unfortunately these are rare. The NOS DAC and software approach is a way to get around trying to find hardware with good digital filters. By doing the oversampling in software you have FAR more flexibility in playing with different filter parameters. For my own DACs I've spent years going back and forth between NOS and digital filters. A NOS DAC with several poles of analog filtering can sound quite good. But the best is still digital filtering done right. Of course that takes significant digital horse power, which means you have to be very carfeful that the noise from the filter doesn't make it into the clock circuits, DAC chips and analog circuits. That takes very careful grounding and PS design, none of which comes cheap. I personally do not like ASRCs. I have not heard a single one that I really like. Of course it may not be the ASRC per se. I expect part of it might be the interaction of the imperfect digital filters in both the ASRC and the DAC chip interacting with each other. On the "HOT DAC" I suspect its due to internal PS noise. As the chips get hotter the FETs in the circuits get higher resistance, which slows them down (RC goes up) so the peak current from each switching goes down, thus less noise on power and ground traces in the chip and package. As the temperature goes up at some point things get so slow it stops working, you don't want to go that far! John S. -- JohnSwenson ------------------------------------------------------------------------ JohnSwenson's Profile: http://forums.slimdevices.com/member.php?userid=5974 View this thread: http://forums.slimdevices.com/showthread.php?t=93483 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/audiophiles
