Review on Douk Audio U3 Mini Class A Headphone Amplifier - HiFi Desktop Home Stereo Amp (DC5V) by Lori Marquez

This thing is incredibly big for what it is. I have other DACs/amps and they are half the size or smaller. Although they are more expensive. The sound quality is not very good. I have high impedance headphones (hd6xx 300 ohms I think) so I bought these because I had a specific device I was using them with and it couldn't handle a high enough volume. This results in LOTS of noise at high volume levels. Not to the point where it goes beyond what you normally hear (unless you listen to high dynamic range genres like classical or jazz), but I use it during my late-night guitar practice sessions, and am with the electric guitar I am usually loud enough not to be heard while playing. When you stop making a noise, it becomes very noticeable. Overall, this is about what I expected at this price point. It almost falls into the junk category, but if you just need to boost the signal and audio quality isn't a big deal, then this will do. Personally if you can afford it I'd buy something else, maybe drop o2 headphones instead of an amp.