sentences:  Their road manager, Ian Stewart contacted Rich Mandella at the Ampeg office in Hollywood, and Rich arranged for the band to use five prototype high-output amplifier heads of a new model being developed by Bill Hughes and Roger Cox.These new amps employed a 14-tube design to generate 300 watts of power in an era when most tube amps generated less than 100.The Rolling Stones took these prototype Ampeg amps on tour along with Rich Mandella, playing all guitars and basses through them for the entire tour.