Pros: It works
Cons: Does so many things wrong
I found this DAC kind of meh. $699 (currently on $669 special) is sort of no-mans land is terms of DACs. It's admirable that Matrix put out something at this price point - especially balanced outputs. In terms of my expectations at $699, I wouldn't expect the utmost resolution, but I would at least want something that doesn't do anything terribly wrong.
The impressions below are from the balanced outputs (I think it's fair that this review focus on that, after all, this is a balanced out DAC.) The amp used was an Eddie Current Balancing Act with 7N7 NU tall bottle driver and EML solid-plate 300Bs. Headphones were HD800. Interface was USB from PC with J River.
Tonally, this DAC is fairly neutral and doesn't have anything wonky in the FR. That is good. However this DAC makes too many mistakes (and the extent of these mistakes are signficant, not minor.):
1. Lacks macro-dynamics. Very serious problem. Can't capture the roar of large symphonic works. (major)
2. Flat sounding - not able to pull of those little instantaneous dynamic contrasts which bring immediacy to reproduced sounds. (moderate)
3. Muddy bass. (major)
4. Slow sounding with poor transient speed or late transients. (moderate)
5. Lacks air. (minor)
6. Treble harshness / glare (minor)
7. Lacks deepest bass (can be overlooked at price)
You are better off with an AMB Gamma 2 (used or built by MisterX) or Schitt Bifrost. If you want to spend $50 more, get the upcoming Schitt balanced DAC (if you need balanced). These three DACs I just mentioned aren't perfect either, but they don't do so many things so wrong to such a large extent.
I really like Tam at tamaudio (I loved the Matrix M-stage amp), but I just can't recommend this to any of my friends if they were looking for a ~$700 DAC.
Two Stars = Needs Improvement (I never give A grades / five stars to equipment.)
Two and Half Stars for the SE output (which does sound better than the balanced outs.)