The Yellowcake Lida Machine at it's heart is a simple LFO filter with the usual rate, depth, frequency, and feedback controls. But this is not a MuTron-style envelope follower. It doesn’t react to your playing dynamics. The filter frequency simply sweeps back and forth according to the LFO rate setting. Nor are there multiple filter types: just your basic resonant low-pass filter with smooth, triangle-wave modulation. There’s also a master volume control, a wet/dry mix knob, and a switch that toggles between slow and fast rate ranges.
But this simple filter sounds terrific. The op amp’s sound quality is excellent. The ranges and tapers of the pots are wisely chosen. The sweet spots are never clumped together at one end of the knobs’ ranges, and every possible setting is usable. The sweeps teeter into self-oscillation with the feedback knob above 4 o’clock or so. Lida will shriek on command, but there are plenty of subtle sounds, too.
And that’s just the foundation.