Snake oil…?

[LektroiD]

This synthesizer module has just hit the market, claiming that the box of dirt glued to the back of it will "add an earthy character to incoming sound". 

http://www.factmag.com/2015/09/24/erd-erd-dirt-eurorack-synth-module/

[EEVblog]

Actually, it probably does what it says - it ads distortion.

[LektroiD]

Distortion circuits are easy to make with a few diodes. I can't see how a box of dirt is going to do anything. Maybe you can get a little resistance from it, but what happens once the dirt has dried out inside a warm synthesizer...

[GNU_Ninja]

Where there's muck there's Brass 

High gain amp, couple of wires stuck into a box of dirt ... Yeah, that would generate a 'signal' of sorts.

I think I'll breadboard one up for a laugh