This board is a dual utility LFO offering manually variable wave shapes. Standard waveshapes are falling ramp variable through triangle to rising ramp, and variable pulse width. A fixed square is also available, as is a combination waveshape that is variable between the saw/tri output and the square. This is a MIX not a morph. Optional switches allow the variable outputs of the two LFOs to be intermixed.
A little on how it works:
The Utility LFO is based on the standard integrator/schmitt trigger oscillator core. Two pots in the integrator charge path allow for the adjustment of speed, and along with two diodes, for the adjustment of charge versus discharge time. Changing this ratio will allow the triangle/saw output to be adjusted through falling ramp, to triangle to rising ramp. At the same time, the output of the schmitt trigger will reflect this in the length of it output pulse.
A a 0 volt referenced comparator connected to the output of the integrator generates a square wave as there is always an equal portion the ramp/triangle wave above the 0 volt reference, though adjustment of the shape of the ramp/triangle wave does change the phase of this square wave.
Following the comparator is a buffered voltage divider to bring the square wave done to a more suitable level and also to drive one side of the variable output mixer pot. The other side of the variable output mixer pot is connected directly to the integrator output. The variable output is buffered is used post mixer by another op-amp.
Specs & Downloads
Specs & Downloads
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Customer Reviews (1)
- Great circuitReview by David
- This is a very useful and fun module, and is easy to build. The speed range as designed is a little limited, but there are several ways to mod for a slower low end out there on the net. (Posted on 12/17/2016)