Selling my Raven Labs PHA -1 Headphone Amp/Preamp. In excellent working and cosmetic condition. I'm the original owner and it hasn't left the house. New amp has aux in and headphone jack so no need for this any more. Don't have the power adapter but runs on two 9V batteries. $195 plus shipping from CA Product description The PHA-1 is a professional unit that can be used as a headphone practice amp, versatile preamp, or to create your own mix in the studio. The PHA-1 will allow up to two players to plug in and practice together while monitoring their sound via the dual stereo headphone jacks. a stereo source (such as a portable CD player or cassette) can be blended into the overall sound. The left and right mix volumes adjust the levels of the external source, providing the ultimate environment for silent rehearsing, solo or with a fellow musician. Make sure you are in key by hooking up a tuner to the Auxiliary send. The sound of your instrument can be tailored using the 3 band EQ. Immediately noticable will be the sound quality, dynamic range and lack of annoying hiss. The PHA-1 will faithfully reproduce anything from a 5 string bass to the variety of sounds from a synthesizer. Are you done practicing and ready for the gig? The PHA-1 makes the ideal buffer between your instrument and amp. The high input impedance assures that ALL of you instruments tonal characteristics reach your audience. As well, the PHA-1 will provide additional gain and tone adjustments. The Auxiliary send and Stereo mix inputs can now act as a side chain effects loop. Being on a "side chain" insures the integrity of the natural sound of your instrument, while lowering the overall noise created by your effects unit. Use the Line Out to send the signal to your amplifier. The PHA-1 is powered by a pair of 9 volt batteries. Battery installation is easy using the battery compartment on the outside of the chassis. No "unassembly" is required. Battery life will be around 50 hours.