Not again, now he is making noise here after his bashing got booted from diyaudio.com, sorry to expose everybody here for that....
He purchased four pcs rev1 dam1021-01 DIY DAC boards in Jan 2015. In Sept 2016 he emailed and asked to return the units for a full refund, as he "was overwhelmed", which I of course couldn't do, those were pretty old boards, the dam1021 was then at rev 4.... Instead I offered to update them for $25 per board, but he declined that.
The dam1021 started life as a test bench for my R-2R Sign Magnitude DAC Technology, it turned out to be great so I decided to offer them to the DIY community at a pretty low cost. Over time it got improved, like all new products, with suggestions for hardware improvements and free firmware updates.
Apparently he got pissed with me and are now throwing around all kinds of accusations. If you believe him just a little bit I can recommend you to read the main dam1021 thread at diyaudio.com, but it's kinda pretty long....