Indeed for $45 it is very good value for money.
I can finally enjoy my collection of hi-res vinyl rips.
Running the OPUS in passive mode does make it lack a bit of energy and weight and sound a bit flat compared to a dac with an active output stage. I did find it has more delicacy and finesse in the presentation. But less weight/body in the music (which is quite crucial). Probably as we were listening to the 24/96 file compared to the CD on the kdac/audiogd combo. I noticed with Braddles AudioGD which uses the same chip but with an active gain stage, the energy is there (although extra gain stage + spdif input stage) being a downfall as it makes the sound quite muddled/congested and especially highs quite harsh compared to the kdac.
But from my short experience so far with even this basic hi-res setup, I'm starting to appreciate and get an understanding of some of the benefits that hi-res encoded music can deliver..
Maybe something like this 32-bit buffalo with tube output stage is next on the cards for me?
Maybe.... oh wait, it's already sold