Hi orchardaudio,
Interesting design for a modern DAC. Like many of the old NOS DAC’s using the TDA154x chips you seem to be using the TI PCM1794 in parallel to improve the dynamic range and the SNR and THD+N. No mention of it, but I would also expect crosstalk to be improved with your design. It’s an old concept that worked well with the non-overclocking TDA154x chips (introduced in 1985, some people still say that there is nothing better). However, I have a couple of concerns for a DAC with this hefty price-tag:
- Bit rate maxes out at 200kHz, I would have expected 384kHz or even higher.
- It will not support 32bit audio data, only 16bit and 24bit.
- The component count on the board is very high. This increases complexity, the risk of defects and possible causes of quality reduction. These are real challenges specifically for production consistency.
- It is questionable (not only for this board) whether balanced outputs are justified. With long cable runs, then yes. But for short distances, a set of quality RCA cables will provide equally good results.
So, the big questions are how does it sound? And, how does it measure up?
It would be really interesting to blind test your DAC against a HiFiBerry DAC+ Pro (RCA version). This would compare the parallel effects against higher bit rate, bit depth and component count with a board which costs 25% of the price.
I would also be interested in seeing your test results. Independently measured test results for the HiFiBerry DAC+ Pro (RCA version) are published here:
http://archimago.blogspot.com/2016/10/m ... berry.htmljanui
Posted: 23 Mar 2018, 00:13