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AM2470 Module - Eľ Systems Dual LFO
Overview This
module is a clone of the LFO section of the Eľ Modular 2451 Potpourri module. It has two identical LFO's, each with square and triangle waveforms, a frequency control and two level controls. Whilst this is not the most exciting LFO,
with just two waveforms, it is simple and effective.
Original Circuit The Eľ modular originally used wide ranging VCO's which could be set as sub-sonic LFO's, just like Moog and ARP. However in March 1976 Dave Rossum
created a multi-purpose module - the Potpourri (2451), which included a LFO as well as analog and digital inverters.
The circuit is quite traditional, and uses a 741 Op Amp, 556 and 558 Op amps. The frequency range is from 0.02Hz
to 50Hz.
New Circuit The clone uses the same schematic as the original, but has NE5532 Op Amps instead of the impossible to get 556/558. I have added a simple LED drive circuit from the square wave. The frequency
range from the prototype is 0.06 Hz to 32Hz, and the waveforms are clean.
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