Kuro wrote: > > BTW, is there any reason why ESS9023 is not chosen as the DAC chip? One > can buy the AQ Dragonfly for $250 (it was designed by Gordon Rankin and > it runs Streamlength code over the USB, and it uses ESS9023) and you add > a Pogoplug for $25 (Pogoplug + 4GB thumb drive) and you have a very > capable DAC running Squeezelite. If you look around, you can buy the > Dragonfly for around $200 and I got my Pogoplug for $13. This is in the > same price point on the product you guys are trying to build. > >
I have done extensive testing of different DAC chips and digital filters and have come to the conclusion that one of the biggest problem with almost all DAC chips these days is the digital filter. Every one of them (including the ESS) use a complex digital filter rather than something like a true SINC, attempting to get better numbers in the spec sheet without spending the required silicon resourses normally required to get those numbers with a simple filter. My testing has shown that these complex filters are quite audible and one of the biggest detriments to really good sound out there. Using a DAC chip without a digital filter and implementing one in an FPGA using a straight forward basic filter design sounds much better than using the filters in the chips themselves. The chip I'm using (PCM5142) has programmable DSP system inside that lets me turn off the builtin complex filter and use my own simple filter. My experiance has shown that a simple filter with with not quite as good "specs" sounds much better than a complex filter with better specs. John S. ------------------------------------------------------------------------ JohnSwenson's Profile: http://forums.slimdevices.com/member.php?userid=5974 View this thread: http://forums.slimdevices.com/showthread.php?t=97881 _______________________________________________ discuss mailing list discuss@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/discuss
