Review on 🎧 Fosi Audio N2 Headphone Amplifier: Portable Amp with 3.5MM Gain & Bass Switch for HiFi Earphones - Powered Dual-Output, Compatible with iPhone, iPod, iPad, MP3, and Computers by Kenny Outlaw

I have been making high-end home audio equipment for 40 years. Bought this amp for outdoor use. One reason for this is the OPA 1642 class D amplifier. This is a Burr-Brown design. Burr-Brown is well known in audiophile circles for its chips. This particular amplifier is used in both professional audio equipment and more expensive Blu-ray players. This amp will make any headphone wake up and sound better. I wanted to go further and use more complex results. I tested with old Sony MDR EX71 headphones that are probably 20 years old. They were quite expensive back then and have stood the test of time. The soundstage was open and this little amp had a lot of punch and a very natural sound. I then tried my Razer Hammerhead headphones and the bass was overwhelming in the amplified (loud) selection. Unlike Sony, they are designed for gamers. The highs weren't as accurate as the Sony headphones. Then I switched to over-ear headphones. I hooked up my AKG Y500 and the N2's overall dynamics were impressive. Despite being Bluetooth headphones, they really shine when connected directly to a source. The picture was accurate and even at higher volumes I didn't hear any distortion typical of Class D amplifiers. The second headphone I tested was the Sennheiser HD 25s. This is the choice of most DJs. Known for their full spectrum of sounds, they present a full and open soundstage. This little amp had no problem powering them and the sound was full range with very good imaging. Hell comes to mind. The battery didn't die but I played at least 2 hours on each of the 4 devices. I should also mention that the gain and bass controls help the user find the setting that best suits their tastes.