It is quite easy to go down the garden path with digital. There are a lot of variables, even when using a transport, including jitter, digital filtering in the DAC and DAC output stage and power system. Any of these can make it sound "digital".
The best way I have found to approach this challenge is to focus on one thing at a time and optimize it, eliminating that effect as a cause.
The first thing is to eliminate jitter. Trying to do this by selecting a particular DAC just confuses things. Most DACs with resampling in them change the jitter and thereby the sound, but never never eliminate jitter, or even reduce it to inaudible levels. The source must be optimized in order to do this, whether its a transport, USB converter, server, computer or network renderer. With most transports, the best solution is a reclocker, unless you are willing to spend $20K for a transport, which is IMO ridiculous.
Optimizing the DAC digital filter is harder. There are several approaches:
1) DAC that has discrete D/A implementation and custom filters
2) NOS or ladder DAC that has NO digital filtering
3) DAC that has selectable filters
Optimizing your choice in output stage has several options:
1) tube output stage
2) discrete transistor output stage
3) minimum # of op-amps in the output stage
4) active output stage with feedback that linearizes the behavior
Optimizing the DAC power system is much harder. With some DACs that have external power supplies, you can upgrade and improve this. Adding an AC voltage regulator like the Plasmatron from VHaudio.com helps a lot, but not inexpensive.
IMO, trying to use cables or filtering to make it sound more analog is the wrong garden path. It ultimately sacrifices dynamics and detail.
Steve N.
Empirical Audio
