Jitter issues with dacs....

From my job experience with digital electronics I have assumed that the data read in from the disc would go into a buffer memory, and be "clocked out" with precise timing. Parts-per-million would be easy (inexpensive)to do. It would not matter how irregular was the timing of data input from the disc.

I gather that most, if not all, disc players fail to mechanize this approach, and are therefore subject to "jitter" problems. Perhaps this is understandable for a $100 item of equipment, but at high end prices it is inexcusable.

I've been listening to several DACs and CD players over the last year. I enjoyed listening to those with 24/192 upsamlers the most. I attributed this preference to the upsampling.

Well, I tried a Benchmark DAC1, which has no upsampling at all and it had the same characteristics that I liked in the upsampling DACs. After a bit of review, I realized that all the DACs and players I tried (including the Benchmark) had special low-jitter circuits or third party add on clocks to reduce the jitter (in addition to the upsampling).

At this point, it appears that the low jitter was providing a benefit that I completely mis-identified as the "upsampler" effect. I don't know that I can "hear" jitter, but I can identify when it is not there.

-Rick

According to Benchmark Media several months ago, the DAC 1 upsamples to 24/110 via Analog Devices AD1896. They planned to increase the frequency to 192kHz once they were satisfied with the sound. The unit I received two months ago was marked as a 24/192 DAC.

Of course, their claim to fame is immunity to jitter. I'm using the coaxial input with DH Lab's D-75 RCA to BNC interconnect. In any event, the sound is absolutely transparent.

Jitter is a problem with virtually all Transports, particularly stock. Jitter is also increased with lossy S/PDIF cabling. It is aggravated by systems that are not properly impedance matched as well.

I can only speak for myself - I can plainly hear the effects of jitter - they are like echoes or halos around each instrument or like high-frequency sibilance. Adding a Superclock2 to a transport or DAC significantly reduces jitter and this change should be obvious to anyone that is not deaf.