Well, it’s not a pretty story, but I now have three non-functional DAC boards. My best guess (after having three of them quit) is that they failed when I plugged power into them from a 12-volt battery (with the input switch in the S/PDIF position and a live input into the S/PDIF connector.) and creating some sort of transient(???) In contrast, a friend of mine installed one of these in a chassis along with a good 12-volt in-board power supply, and that unit works just fine.
When working, these little DACs boards cost $74 each on eBay, and they do sound pretty good and have decent parts quality, including a couple Burr-Brown ICs. To the seller’s credit, he did give me one of the boards free after the second one failed. I twice tried to send the boards back to him (in Hong Kong)—I figured he could repair one for me and keep the others, or whatever—but the package never got past the Hong Kong post office. Apparently the post office folks never told him they had a package for him. So, the package came back to me.
So, I have three nice little non-functional DAC boards and a schematic diagram. S/PDIF and Toslink inputs. $25 obo shipping included for the whole batch.
