Electric Guitars, Acoustic Guitars, Guitar Amps - American Musical Supply - Musical Instruments and Musical Equipment From our humble beginnings as a catalog music store in 1982 to now serving more than half a million customers world wide, AMS has grown into a top 500 E-retail Business as ranked by Internet Retailer. Tens of thousands of products are offered including guitars, basses, keyboards, recording and live sound equipment, percussion, amps, DJ and lighting gear.