elby designs cgs758 utility lfo price : $210.00

this module 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 wave is also available, as is a combination waveshape that is variable between the tri/saw output and the square. this is a mix not a morph. two switches allow the variable outputs of the two lfos to be intermixed.

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 tri/saw output to be adjusted from a falling ramp through triangle to a rising ramp. at the same time, the output of the schmitt trigger will reflect this in the length of its output pulse.

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 thissquare wave. following the comparator is a buffered voltage divider to bring the square wave down 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 and used post mixer by another op-amp.

the join switch interconnects the two vari outputs by swapping their ramp outputs with each other, so that each output is a combination of that lfo's square wave with the other's ramp. the swap switch reverses the outputs of the second lfo so that (when join is on) one vari output is a combination for both square waves while the other is a combination of both ramps. when join is off, swap merely reverses the direction in which the second lfo's vari knob works.

this module has a maximum current draw of 30ma. it requires 18 hp/te worth of space to fit in a eurorack frame.