This is a review and detailed measurements of the MEIZU Hifi Pro USB-C phone dongle DAC and headphone amplifier. It was kindly purchased and drop shipped to me by a member. The Hifi Pro costs US $45. Note that this is the "Pro" version. It is different than the standard one.The Hifi Pro came in a nicer package than the typical dongle:The braided cord seems more durable than what comes with $9 ones from phone companies. Of course I have no long term usage data to know if it will last longer.In use, the Hifi Pro gets slightly warm but nothing of concern.The Hifi Pro was plug and play on Windows 10. I was pleased that it would shut off when you disconnected the headphone and come back to life when you plugged the headphone back in. On many dongles unless you have a headphone plugged into them on insertion into the USB connector, they will not activate which is annoying.Overall impression was positive as it should be given the higher cost of this dongle.As usual, the first set of tests are as if the unit is a DAC starting with our dashboard:While not quite the 2 volt nominal output that I like to see, 1.75 volts is much closer than many other dongles which cap out at 1 volt.The real eye opener though is the spectrum showing distortion products below -120 dB! In other words, none of them are audible. As it is, it would set the SINAD to 120 dB as well but due to noise floor being higher, it gets limited to 101 dB. As that number though, this is by far the best dongle I have tested:Most dongles don't make it out of the red bucket alone make it into green.Dynamic range is very good for a dongle, providing 17 bits equivalent range:Intermodulation+noise versus level shows the higher level but extremely good distortion at the limit:Yes, it actually beats the Topping DX3 Pro on distortion! Amazing.Also amazing is linearity which is a measure of how accurate the DAC is:I don't think any dongle has come close to this level of performance.32-tone test track resembling "music" again shows very low levels of distortion:Jitter spectrum shows a lot of unwanted signals but their levels is quite low:Distortion versus frequency shows high levels across the board:When this happens it is usually due to ultrasonic noise and that is indeed what we see:Most important measurement and where dongles fall apart is power. Let's look at that into 300 ohm:While noise level is higher than desktop reference, it is still very good for a dongle. Output power actually comes near what DX3 Pro provides in low gain mode.The Hifi Pro really shines when testing into 33 ohm load:We have nearly 90 milliwatts of power out of this little dongle! And with no clipping or distortion at max. This level of power is chart busting:Output impedance is very low and hence the reason for high power level into low impedance loads:The most brutal test for such a dongle would be my 25 ohm and inefficient closed back Ether CX headphones. While the sound was not great, I was pleased that the Hifi Pro did not fall apart. There was just enough power although bass impact was not what I like to see.Switching to Sennheiser HD-650 provided ample dynamic range, detail and fidelity with no hint of distortion. Hard to imagine this level of performance was coming out of this little dongle.Finally I tested with my Hifiman HE-400i. This was a delight with enough volume where I reduced levels by 3 to 4 dB for comfortable listening. Excellent fidelity was had with again, zero hint of distortion.I must confess that I am not a fan of testing these dongles because they mostly, well, suck.Not so with MEIZU Hifi Pro. This is a level of performance that you don't have to apologize for. If I ever get stuck with a phone or tablet that doesn't have a headphone jack, this dongle would be my choice.Needless to say,------------As always, questions, comments, recommendations, etc. are welcome.The yard cleaning I did a couple of days ago is getting back to me in the form of injured muscle in my chest. Hate not being young anymore! Anyway, I hear relaxing in a tub while eating expensive sushi and having your toes massaged is the cure for it. So would you pleased be kind andusing: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/