The EAD DACs that I use are the DSP 7000 EAD models that were state of the art at the time they were made. Obviously, the clocking is no where near as advanced as a modern DAC, and the 20-bit Burr Brown chip is old by modern standards. I am trying to ascertain, how much of a problem this is, or even whether or not is a problem.
For one thing, the trusty PCM63 arguably is good for the best results among all classic multibit DACs, as it can be trimmed out to a very good degree of linearity. I would want to verify that the EAD can accept and decode 24-bit input properly (or at least the first 20 bits, which would be good enough), as you are much more likely to find straight 24-bit output than special treatment for 16-bit equipment these days.
That being said, you can probably find performance as good as this or better for $200 in a modern-day DAC.
I haven't found anything within the computer realm that I liked for doing the HDCD decoding prior to entering a DAC.
Why not? I see no indications for anything relevant not being implemented.
Also, that method requires a 24 bit file, and I am keeping things at 16 bits.
Why? It's 2023. Any potato can play 24-bit content. Do you have that many HDCDs that actually make use of HDCD features
(most notably, peak extension) for any difference in file size to matter? (There are various ways of scanning the files and identifying features used, e.g. you get a context menu option after installing foo_hdcd in Foobar2000.)
For the handful of HDCDs that have found their way into my own collection, it's pretty much been a "software decode them, dither to 16 bits and forget about it" affair here. This is about all the fuss the format deserves nowadays. I wouldn't want to be dragging a 25-year-old solution behind me like a dead deer.
(Not like I'm a stranger to things like this. My mom always wonders why I won't ditch my 2001 art grade A3 scanner - with autofocus
no less - and 2005 laser printer for an MFP with ADF and all that jazz. It would be more practical, but I'm not really keen on a cheap CIS scanner.)