Ampeg began in 1946 with Everett Hull’s tailpin transducer for upright bass. Jess Oliver later engineered the B-15’s flip-top chassis. It defined studio bass tone for decades—but only for players who matched its physical and sonic constraints.
The Ampeg SVT is a 1969 bass amplifier head designed by Bill Hughes and Roger Cox. It uses 14 vacuum tubes to deliver 300 watts of RMS power. Early units used unstable 6146B output tubes, later replaced with 6550s. It is a stand-alone head, not a combo. The Rolling Stones used five prototypes on tour in 1969, playing all guitars and basses through them.