EH-7810 Memory Man

See also the EH 1338 designator. I have not verified any differences, but this would appear to be the schematic for 1338. The color schemes may be different in addition to any circuit changes.

NE5554 voltage regulator.  This also pops up in the original Micro Synthesizer schematic.  This part was probably deemed too expensive/excessive when a simple transistor regulator does the job just fine.  All of the op amps on this Memory Man have 30V (+/-15) power supplies, unlike most versions where the supply is only 15V.

This Memory Man includes a MN3005 delay chip, but no compander.

Also interesting on this Memory Man is a “high freq.” trim pot just after the “cancel” trim (called “clock balance” here).  The 100k variable resistor and the 4.7nF cap set a simple -6dB/oct low pass filter.

A3B forms another unique feature of EH 7810.  A3B is a LFO, but its dc output is also variable via the DELAY control attached to pin 5.  A3A buffers the CV on its way to the 4047 clock.  The CHORUS/ECHO switch activates or deactivates the oscillation.