Originally Posted by Argybargy
My unit was defective on arrival. 7.5db channel imbalance. Currently awaiting an exchange. Fwiw, it sounded pretty good using an external psu. The stock wallwart is garbage.
The new unit arrived and no channel imbalance this time.
Stock, this DAC sounds like utter crap... but there's potential there.
First, toss the useless power adapter. Until I build a PSU, I'm using a cheap 2A regulated PS, ~$20 model from Parts Express. Huge improvement right there.
Next, the stock OpAmps are garbage fakes. I hear very noticeable clipping and when I up the PS voltage to 12V most of the distortion disappears but the SQ is still not there. Obviously re-marked cheap fakes. The single I swapped with a Opa827 and the pair with BB Opa2227P. Now it gets interesting.
The cheapO no-name big cap was swapped for 2x2200uf Nichicons with a 1uf polyester bypass = better bass response.
Similarly, the 4 no-name matching caps were swapped for Nichicons. The small gold nichicons looked genuine so I left them as is. There were reports in another forum that the Sanyo Oscons were defective in an early production run, so out they went. While swapping the little one, I noticed that the polarity was reversed from what was shown on the PCB. So either the PCB is wrong or it was installed wrong. Who knows, I just put in a bipolar nichicon Muse.
All the parts might be a little pricey considering this is a $99 DAC (I had all the parts except for 1 opamp so I actually only spent $10) but wow this thing sounds great!
The soundstage is big; nicely extended treble; excellent full bodied bass; and a clean detailed and dynamic sound.