My D18 needs to be warmed up for 6min before playing 24/192, or else I'll get a brief drop every minute or two. In my tests I warmed up everything else in my system for a long time before turning on the D18. The 6min can be spent playing music or just being on, so that doesn't matter. Today I did the same test with 16/44 and there were no drops at all. I wanted to test 24/96 on a cold D18 as well before posting this statement (and retest all of this) but I'm curious if your drops persists after 6min. My TubeDAC-11 required a 20-30min warmup before 24/96 playback (every other freq was fine if you'll believe that), and inserting the JKSPDIF did not fix my issue. I'll test 24/96 tomorrow.
To me the pricing of these usb2spdif adapters does not reflect the engineering and materials that went into them. Even the relatively affordable Hiface 2 looks like nothing more then a $25 Turtle Beach USB sound card. I can get a Core-i3 laptop with a 15.6" screen for $400 new, but I can't get an Audiophilleo 1 with a 1" screen for $700 used.
I got the JK because it came up used on Audiogon (shipped for $385 from Korea w/ the attenuator) but I still have to remind myself that this is a niche market that cannot enjoy the economies of scale. And I was at peace with my purchase until slickdeals.net informed me that Intel is selling an i7 3770K Ivy bridge for $230!
If I were you I would take a chance on the $100 NuForce U192S from some place that has a good return policy. Sample rate LEDs are fun! It doesn't use an external PSU, but neither does the Hiface 2 and that seams to get the job done. But if your tired of disappointment then I'd get one of these...
...or spend the extra bucks on the powered U18.