So i bought this used, just wanted to post this review because this really is an amazing DAC and even at retail value it is fully worth the price. It's a bit of a shame that Audiophonics discontinued it.
I use mine connected via USB to a computer running Roon.
Outputs to a Rotel pre and power amp driving a pair of B&W CDM7 SE speakers.
I'm not really sure about the filters but i listen to a lot of slow/ambient electronic music and prefer the slow roll filter in general, it seems to make the bass roll off in a smoother fashion.
However there's one quirk with mine (maybe can be fixed with software update? If Audiophonics can chime in that'd be much appreciated).
So when i turn it on and play files from different sample rates the display will get stuck and the source/filter button doesn't work anymore so the DAC needs to be restarted.
A workaround i've found to this issue is just switching the channel back and forth back to USB again first thing after power up
So a minor annoyance which i will gladly oversee, but would be nice to get fixed.
Overall superb value for money.