A tube or solid-state circuit used to send signal through a spring reverb, usually in a guitar amplifier or sometimes in a stand-alone unit, such as the Fender ’63 Reverb. Leo Fender used the 12at7 tube as his reverb driver because, despite usually being used as a preamp tube, the 12at7 has high current capability, and can drive a reverb spring (or even a speaker).
