I received the D2 and Ryan from Maverick Audio said it would take a full week to burn-in. He said to leave it on continuously but because there is a tube in the circuit that is always on (even if you are not using the tube output) I turned it off quite often and let it cool down. The SS output sounds clean and noise free and the tube output sounds very similar to me but with a slightly reduced treble. The tube output sounds smooth and is also completely free of any noise. I am still letting it burn in and just getting into evaluating the external DAC. I can say it sounds better than all my optical drives with better resolution and detail. It's not night and day but you can hear that the sound quality has improved. There were a couple of slight issue's when I received the unit, first the chassis was racked and sat on 3 of the 4 feet and the top has a slight dent. The box looked fine so I don't know what else could have been done to prevent damage. Ryan has worked with me on this and has offered to refund a percentage of the purchase price, I haven't received the refund as of yet but will update when I do.
Even though this is my first DAC and there were a few issue's with shipping from China I'm happy with the purchase. The unit functions perfectly and offers 3 different inputs as well as 2 outputs, both tube and SS. I am going to continue to allow it to burn-in and spend time evaluating the tube and SS outputs with different amps. I will post again when I think the burn-in is complete and have tried some different configurations.