This is a review and detailed measurements of Loxjie D10 USB DAC and headphone amplifier. It was kindly sent in by the company for review. The D10 costs US $129 on Amazon including Prime shipping.Similar to other Loxjie products, the D10 comes in unusual shape and has a choice of red and blue colors:Putting aside the very sharp corners, the overall feel is good. Usability is not though seeing how the LED indicators are the left side:Worst yet are the super tiny fonts as you can see (or not). And the LEDs seem to do double duty showing levels or something. I am not sure.The situation gets more complicated seeing how the headphone jack is placed on the other side together with the rest of the rest of connectivity:The headphone jack should have been in the front at least. As it is, somehow you have to manage your cable situation.Another odd choice is the micro USB connectors. Why? This is such a large box and so should have standard large USB type B connectors.There is a second USB input as you see for power. I am assuming it is needed for Coax/Optical input as using it with USB didn't do anything. So you could power the unit with just the one USB jack.Anyway, I appreciate the attempt to make a different looking unit. Some points need to be given for that.Note that you can turn the headphone output on and off using a button for people who appreciate that.As usual, let's characterize the DAC portion separately from the headphone amplifier by measuring what comes out of the RCA line outs:Wow, that is pretty good THD+N distortion and noise. The equivalent SINAD nicely places the D10 in the top bucket of all DACs tested regardless of price:Output voltage is about 1 dB higher than we need. I dialed it down to get 2 volt but performance remained the same so I stayed with full value for the rest of the tests.Good news extended to jitter performance:Linearity was perfect:Multitone shows some rise in distortion as frequencies go higher but still very good:Dynamic range was also very good:Our hearing dynamic range is about 116 dB so we are definitely transparent here.Any bad news? Sadly there is one:The ESS DAC chip IMD Hump attacks us with vengeance. The very good performance of the D10 otherwise makes it more pronounced than would be if say, the noise floor was higher. Such a shame that ESS did not solve this problem on their own and communicated the solution to all of their customers.Reconstruction filter is excellent, staying flat to 20 kHz but then truncating very well at half the sampling rate of 22.05 kHz:Let's start with distortion and noise versus power using 300 ohm load:We generally have good noise and distortion but power is not that high.Switching to 33 ohm shows current delivery is not so good:Distortion/noise climb good bit and we lack power to even match the Topping DX3 Pro in low gain. Usage of USB power for everything likely limits performance.Output impedance of 3.9 is decentEDIT: Original review had the incorrect value for output impedance.Measuring signal to noise ratio at just 50 millivolt to simulate what happens with very sensitive IEMs, we get an uninspiring number:I started testing with Sennheiser HD-650 headphones. Here power was pretty reasonable. The sound would get bright toward the last 25% but that is probably too high a level for many people.Next, I went the other extreme with the DROP + MRSPEAKERS ETHER CX with its DC resistance of just 22 ohm. Predictably, the bass notes completely fell apart with each beat at medium to high listening levels. Just not usable here unless you want just background music.The situation improved a bit with Hifiman HE400i. I could get louder with these before the bass started to distort.The Loxjie D10 has an innovative form factor and industrial design. It has equal pluses and minuses in practice so I let you judge that aspect. On performance front, its DAC nearly aces all of my tests, going well past its budget pricing. Unfortunately the ESS IMD Hump is there, knocking it back a step or two. Still, I think it provides a very good option for a DAC at such a reasonable price.On the headphone front, its performance just doesn't match that of the DAC. It is good enough as a "free" option on top of a good DAC. And could be used with sensitive headphones for everyday use. Just don't expect any miracles from it.Overall,------------As always, questions, comments, recommendations, etc. are welcome.I hope you are happy with the pace of reviews as of late. Plan to take a little road trip middle of this coming week. As you can imagine, it cost money to do that so pleaseusing: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/