Many vintage EF86 circuits copied datasheet examples that were intended for use in high-gain audio amplifiers, microphone pre-amplifiers and magnetic tape recorders. This approach contributed to the EF86's (unfortunate) reputation for being noisy and microphonic among guitar players. Current production amps, based on vintage circuits, may exhibit these same tendencies. However, when we chose the EF86, we started over with a guitar amplifier in mind, and we designed a circuit to suit that application. The result is a great sounding amp without the issues typically associated with earlier examples.