1964 VOX REVERB UNIT JMI Product Code EF588

Highly prized valve reverb and preamp unit Ser. No: 1714. Very clean cosmetics with grey JMI logo control panel. Knobs, handle etc. all original. Electrics all original apart from some caps. All in very good working conditions.

The Vox Echo-Reverberation circuit featured four tubes, dual channels and point-to-point hand wired construction. The delay line, including transducers and transmission springs, was suspended inside the chassis on two rubber bands. One half of V1, a 12AX7, was the gain stage for the first channel. The other half of V1 was the gain stage for the second channel. V1 worked in conjunction with the 1/4" inputs and the channel 1 and 2 level controls. Both triodes of V3, a 12AU7, powered the signal to the drive transducer. V3 worked in conjunction with the Reverberation Length control. Advancing the Reverberaton Length control increased the amount of signal delivered to the drive transducer. One half of V4, another 12AX7, powered the return signal from the receive transducer. V4 worked in conjunction with the Reverberation Level control. The Reverberation Level control balanced the output of the "wet," or delayed signal with the "dry," or original signal.