Further Experimenting with SDTrans 3.0
Update (6/9/11): The latest version of the Hifiduino code with settings for the quantizer bit length greatly reduces this noise problem [link]
…Last day with SDTrans. My loan period is over 😦
I would like to express my gratitude to Mr. Bunpei for graciously offering to loan me the latest version of the transport.
At the minimum, I had to try 24 Bit/352.8KHz material. I downloaded B.Britten: Simple Symphony, Op. 4 – Boisterous Bourrée from 2L.
It played almost well with Buffalo II. It sounded BIG. Room filling BIG!. Very nice piece with great dynamics.
However, with Buffalo II 80 MHz, it showed some low level “crackle” noise when playing. When paused, there was a loud hiss which was independent of the volume setting.
A quick look at the SDTrans thread at diyaudio indicated that this is “normal” behavior (reported one year ago -I am way behind this ultra-hi-res audio :-)). The solution seems replacing the 80 MHz oscillator with a higher frequency one. The latest version of Buffalo II does come with a 100 Mhz oscillator.
Even so, Buffalo II was able to lock into the signal with “best” setting in the DPLL
Finally, I measured the LRCK signal for 352.8KHz with my new scope. The shape of the waveform is most likely due to the scope rather than SDTrans (still learning how to use the scope)