After years of relying on other equipment to drive Grado headphones, you can now listen and enjoy headphones through Grado Labs' Reference Headphone Amp, the RA1. Designed for state-of-the-art performance and specifically to play Grados, the RA1 will allow you to hear your headphones like never before. This amp is machined from a solid block of mahogany and measures 5" wide, 5 1/2" deep and 1 1/2" tall and weighs in at 12 oz. The RA1 is available in an AC version or can be powered by two 9-Volt batteries that will drive the amp for 40 to 50 hours of listening pleasure. And the sound? Just like all Grados: warm, smooth, full-bodied, non-fatiguing and rich. Hook it up to any line source (portable or in-home) and drive your Grado headphones to their full potential.