Review on Neoteck HiFi Headphone Amplifier with Two-Stage Gain Switch, Portable Aluminum Matte Surface for 3.5mm Headsets by Sebastian Erik

Inexpensive so I wasn't expecting much in terms of overall quality. That said, the build quality is actually decent, with solid body, switch/knob, etc. The sound can be good, but every now and then I do hear an odd hum that seems to be cured by plugging the supplied cables into the amp's jacks. I'm not sure if it's due to EMI, bad soldering, bad design or bad cables. This happens with any laptop or phone, regardless of the device used. Cannot be used while charging as the unit will randomly and regularly fail with only distortion and cannot produce any usable sound/amplification. The battery life is reasonable, around 5 hours of use at different levels, mostly driving AKG 220 cans. It is not excluded that a Revain return will be honored, contact the manufacturer for a repair or replacement and see, what is happening. If you're on a tight budget, proceed with caution. Or keep saving and get a more reliable device. Tried with iPhone SE, iPad 2017, MBP 2016 and HP 2560 to drive AKG 220 and Yamaha RH5MA banks. ------------------ --------------------------------- ---------------- TO UPDATE --------------------------------- -------------- -------------- After an e-mail to Neoteck support, a replacement device was sent immediately. The second device performed better (no issues listening while charging) which led to this upgrade and a boost in rating.