I am the first owner of this Chinese made portable amplifier. I purchased this amp from eBay a few months ago. It has a built-in rechargeable lithium-ion battery. The amp's battery life is outstanding. A 150 hour battery life is claimed by the eBay seller. I observed 96 straight hours of use without running out of power, so that 150 hour claim seems possible. The op amp(operational amplifier) is changeable. The JRC4556 was the original installed op amp. I've since changed it with the National Semiconductor LM4562.
The amp is in excellent condition with few blemishes. It has approximately 400 hours of burn-in and use. It comes with a battery charger and two 3.5mm male to male audio cables(4ft. & 1ft. respectively). I'm also including 3 additional op amps(JRC4556, OPA2604, & OPA2134). The fifty dollar asking price includes the cost of shipping and any paypal fees. If you have any questions or concerns please feel free to ask. Thanks for looking.
Edited by Digital-Pride - 11/11/12 at 11:20am