Fender '59 Bassman The '59 Bassman, chosen by legendary guitarists like Buddy Guy, Brian Setzer, and Jeff Beck from among countless guitar amps, and even copied by Marshall when they were starting out. The high-frequency response and sound clarity achieved by the four 10-inch speakers allow for a picking nuance that sets it apart from other amps. Maintenance performed: Vacuum tube measurement, measurement of each element's constants, bias adjustment, socket and contact cleaning. This is an amp ready for immediate use.