Premium Headphone Amplifier with Bass Boost - 3.5mm AUX & USB-C Input (16-600Ω) - Gain Control & Stereo Audio Output for Enhanced Sound - Compatible with Mac, iPhone, iPad, Android, PC, Xbox, PS4, PS5 - Perfect for Gaming, Music Production & Home Entertainment

What's up with cell phone manufacturers removing the headphone jack, right?The paranoid among us know using Bluetooth is a potential security risk. The Audiophiles among us know there are limitations in the on-board analog audio and Bluetooth digital stream. Although this device does not have the quality of a several hundred euro/dollar DAC, it is good. I use it though AKG open back headphones,Bose closed-back earphones, and Sennheiser earbuds. It sounds good.First the audio: It works well with the USB input source. It worked with my Samsung phones and tablets. No hesitation, it was just like plugging in a headphone right into a jack. Worked just as well on my Windows desktop.In-line with the audio out (headphone) jack on the desktop and my tablet worked just as well. A definite improvement over simply plugging the headphones straight-in; more mid-range and base, a deeper sound stage, but maybe some narrowing. You can get even more bass with the enhanced bass equalizer setting. I can't say how long the battery lasts, though (more on that later).All in all, it is quite a functional DAC/adapter, no significant sound color, no static, hiss, or added noise. It is not as good as my desktop audio interface, but it's 5% of the price!Construction: Nice brushed and anodized aluminum case, Feels sturdy; if a bit heavy.Controls: Volume knob is silky; with a definite audible 'click' when you turn it on or off. On the 'front' with the volume control knob, there is a bass boost equalizer. On the back is an switch for high impedance headphones. You'll know if you're using high impedance headphones, and it's nice to have that feature. I found the slide switch on the back to be a little awkward, but you don't change it much unless you're changing headphones. The bass boos and impedance switch are tiny and a little award to use.BUT, be careful of running the battery all the way down. I may have left the unit on and completely drained the batter. Trying to use it from the totally discharged state was as if it stopped working. It wouldn't show the blinking charge light after totally exhausting the battery. Neither in-line or USB modes produced sound. Fortunately this was, within the warranted period. Amazon is replacied it with the same device. Did running the battery down damage it? Is it so heavy that it broke a conductor in the USB connector? Was it simply a production mortality issue? I have no idea why.I would still recommend the device. But I'd also recommend you seriously use the device during the initial 90 days to make sure it will provide you with a quality alternative to the missing headphone jack.