Modular for the Masses Mantis Ladder

Filter

The ManitsLadder is a classic diode ladder with a few twists.

First, it uses precision stable voltage references for several important parts of the circuit. Ladder filters are particularly vulnerable to power rail noise, and this banishes that particular source of noise far far away.

Another quirk of ladder filters is that they lose amplitude when the resonance is turned up. While prototyping this, I was pleased to find that this behavior could be banished far far away also, with just a simple resistor.

It's easy to heavily overdrive the input of this filter, which sounds wonderful. It's possible to saturate the output of this filter, adding even more analog "warmth" to whatever you're putting through this. The volume knob goes from zero to full volume by the time it reaches about 2 o'clock, and after that it's soft-clipping the output against a pair of diodes.

Okay, here's one of the best knobs on this filter: the Inversion knob. This knob feeds an inverted copy of the input signal into the output buffer. If this filter was well behaved and linear, this knob could turn this into a reasonable high-pass filter. And if you're careful, you can get that kind of behaviour out of this module. But if you're not careful, you can mellow a signal right out with the overdrive, filtering and saturation options available, but then bring the harsh sharp-edged features of the incoming signal back in with that Inversion knob. Experimentation strongly encouraged.

https://modularforthemasses.square.site/product/MantisLadder/5?cp=true&sa=true&sbp=false&q=false