This is a review and detailed measurements of the HIDIZS S8 USB-C DAC and Headphone Amplifier. It was kindly sent to me by the company. It is a new product and I don't see it broadly advertised. I only found one site selling it for US $129. So quite high for a dongle.The box is much larger than the unit itself which weighs next to nothing:Three different adapter cables are provided to mate it to USB-C, Apple Lightning and straight-through so should work with any phone.The up down buttons work well.I tested the S8 on Windows 10 which recognized it properly (you have to plug-in the headphone first). Alas, the ASIO4ALL interface I use to test audio products with my analyzer truncated 24 bit samples to 16 bit as it sometimes does. For this reason, I had to run a number of tests manually and a few I had to leave out. But I think you will get a good picture of its performance as is.FYI, the company contacted me after I reviewed one of their products that I did not give high marks to. Instead of complaining, they politely asked if I would review a new product and I said sure. Here we are.As usual we start with our dashboard of 1 kHz tone:Wow, are you seeing what I am seeing? SINAD (distortion+noise relative to our signal) of 114 dB? This is excellent for a desktop DAC let alone one that is the size of a few grains of rice! Here is how it ranks among all DACs tested regardless of cost:As noted, we are talking totally inaudible distortion at less than -120 dB! This is stunning achievement.Even though this is a tiny dongle, it still manages to produce the full 2 volts that desktop products produce. In other words, you can use the S8 for a desktop DAC and not leave any performance and usability behind.Above test was using WASAPI exclusive mode by the way so there is no truncation to 16 bits. Same with the few other tests to follow.Dynamic range was again near top of the class for desktop products:I think the best I have ever measured of any device is 126 dB or so!Jitter is by far cleaner than any dongle I have tested:Multitone shows what we already know about very low distortion levels:For these sweeps I had to use the standard interface which truncated to 16 bits. So don't run with the distortion metrics. First, power into 300 Ohm load:The "high" 2 volt output translates into very good power output for a small dongle:Switching to 33 ohm rewards us with more power as we like to see:The reason for high output with 33 ohm load is very low output impedance (so little losses in the device itself):I started with Sennheiser HD-650. Here, there was just enough volume to be useful in my test tracks. The fidelity was there but not the huge bass impact you get with desktop products.Switching to my inefficient and low impedance 25 ohm Drop Ether CX headphones, I was surprised at the amount of power and fidelity.Best performance was had with Hifiman HE-400i. There was now plenty of volume with very clean, detailed and high fidelity sound.What a pleasant surprise the HIDIZS S8 is. Sometimes you want the best and the best is delivered here with S8. It produces vanishingly low distortion and excellent dynamic range. Even at max volume, there is no clipping so what you hear is as transparent as it can get. Yet, it is delivered in a tiny little package that won't weigh down your pocket or phone.Yes, it is much more expensive than $9 dongles. But in absolute terms $120 is not much given that it produces desktop level performance as well and there, you can't get this kind of performance for $9.It is my pleasure to strongly recommend the HIDIZS S8. It will be the one I would carry on the plane with me to listen with.------------As always, questions, comments, recommendations, etc. are welcome.Since I started speaker testing, my inbox has exploded with private messages. I need to hire someone really smart to answer them as if he/she is me. Such people are expensive to hire. So pleasewhat you can before I burn out using