EH 7850 Deluxe Memory Man with Chorus/Vibrato

Designators for trim controls refer to this calibration guide: EH 7850 Deluxe Memory Man Calibration

The classic 5 knob Memory Man.  This was reissued in the late ’90s/early ’00s under the EC 2002 designator.  Early reissues have a hardwired 3 prong power cable.  This was likely deleted due to modern safety regulations, or perhaps to lower the internal component count/cost.

While the EH 7810 and EH 7811 boards were granted full 30V (+/-15) power supplies, the mighty 5 knob makes due with just a single -15V power rail.

The Chorus/Vibrato switch brings an additional capacitor in and out of circuit for a coarse adjustment to the modulation oscillator’s rate.  (Chorus = slower, Vibrato = faster)

The Chorus/Vibrato control is a simple attenuator that connects the LFO (modulation oscillator) to the 4047 clock.

By just counting knobs, the EH 7850 is the king of the Memory Men.  It’s too bad it lacks the pseudo-stereo output of EH 7811, or EH7811’s neat bypass trickery.  If I were to do a copy of these pedals, I would combine the features of EH 7850 and EH 7811.

Below: EH 7850 schematic.