Review on Portable Headphone Amp With 3.5Mm Stereo Audio Out, GAIN Support & Lithium Battery - Compatible With IPhone/Cellular Phone/MP3/MP4 /Computers. by Robert Ewing

I purchased a small low end keyboard so that I may practice the piano when traveling. I needed a small keyboard as I couldn't carry a large one. I practice with a headset so as not to wake up my friends, but the sound was so soft that I struggled to hear what I was playing. I went to Guitar Center and all of their headphone amps were huge and expensive, designed for professionals.This headphone amp is small enough to fit in my case and weighs practically nothing. Inexpensive but most importantly it works! I can hear what I am playing very clearly and I never needed to switch to the high gain setting (Hi gain adds some more Dbs). The sound is exactly as the keyboard produces only loud enough so that I can clearly hear it. It is just what I needed and works very well.