- Mar 16, 2013
if you dont mind could you explain how OS and NOS DACs tie in here aswell?
Trouble with NOS multibit R2R DACs is the ability to process high enough bit resolution on digital input in an acceptable price. More the bits processed higher the price. The delta sigma design is much cheaper in the regard. But it needs lot of treatment.
The solution I prefer is using HQPlayer to convert all music content on the fly (during playback) to the highest rate DSD the DAC is allowing on its digital input. DSD128 as a minimum suitable for this purpose. Then to use a DAC which does minimal digital processing with DSD signal input. The goal is to complete skip the hardware oversampling process within delta sigma DAC chips. In the case of some DAC chips (from TI Burr Brown, Cirrus Logic) it is also possible to skip the delta sigma modulator and to use the DAC chip purely for digital to analog conversion. No volume control is then possible on DAC chip level with such digitally non processed DSD input. You can find an example of such direct DSD path on picture for CS4398.
When using DSD input with Sabre DAC chips, volume control within DAC chip is possible, because the input DSD signal always goes through delta sigma modulator, but without any sample rate change. No direct DSD path is available within Sabre DAC chips, but no traditional DSD to PCM conversion occurs within Sabre DAC chips to allow volume control. Series of n bits of DSD signal is most probably processed as 'moving window' (one bit in, one bit out) on the original DSD signal rate, so the lossy effect of DSD to PCM conversion, called decimation, is not present in this case. Regarding the volume control itself, HQPlayer does it in much higher precision (using 64bit floating point resolution for computing), so it is better to do it in software if it is needed. Some people think that Sabre DACs sound better with DSD input when no on chip volume control (0 dB setting) is used. I'm able to hear many other differences but I'm not convinced I could distinguish this one in blind test.
I never listened music with high quality multibit DAC like Yggdrasil. I consider it to be too expensive. I compared by listening only delta sigma designs and the HQPlayer / DSD way sounded me always better. With some USB input treatment (not using +5V from computer, as short USB cable as possible, not leading ground wire near DATA wires) I reached better result than with USB to SPDIF converters and DAC coax input. I'm using HQPlayer and DSD solution about 5 years already.