Saturday, May 07, 2011

LFO's A-145 and A-147

Low Frequency Oscillators or LFO's produce periodic control voltages that can be used as a modulation source for all kinds of other modules.

The A-145 LFO1 was the first and one the most basic single Low Frequency Oscillators that Doepfer sold.
It provides 5 different waveforms; sine,sawtooth, triangle, pulse and inverted sawtooth ,and each waveform has their individual (and simultaneous) output.
With the Frequency-knob and the 3-way switch you can select a wide range of frequencies, from on cycle every minute up to audio frequency at the highest.
A reset input allows you to synchronize the LFO signal to an external trigger signal and each trigger will re-start the waveform from its zero-point.

The most obvious use for an LFO is to do some pitch modulation on a VCO to create a vibrato and to modulate amplifiers (VCA's) for a tremolo effect, but with a creative mind you can use these two modules for all kinds of sound manipulating.

The A-147 Voltage Controlled LFO is basically the same LFO as the A-145.
It doesn't have one of the A-145's sawtooth waves, but does have an extra Control Voltage input that is very useful.
Think of an A-174-2 Wheels Module or A-174-1 Joystick Controller as the most used control voltages, but dare to think further... how about controlling the A-147 frequency with noise or perhaps another LFO for example?
My personal favorite use is to put a voltage of an A-198 Ribbon Controller or Theremin Voltage though the CV input and send it to an VCA to get a tremolo effect, but at a higher frequency in the higher notes.

I will discuss the A-146 LFO2 in a future post because it is a slightly different module with different features and uses.

1 comment:

  1. Cool! I didn't get a LFO module for my system yet as I can use a combination of the LFO out from my Dark Energy (which is a simple triangle or square, but very handy) and the envelopes from my quad ADSR module which I can set to trigger themselves. The cool thing with this last solution is that you can create LFO shapes with flexible waveshapes just by altering attack and decay on the envelope. Got to love modular synths! :-)

    Marc JX8P