US Patent 3,475,623:
Electronic High-pass and Low-pass Filters Employing the Base-to-Emitter Resistance of Bipolar Transistors
“I have been collecting copies of Moog patents, those invented by Robert Moog and as well as those assigned to Moog Music, Inc., and the synthesizer-related patents of Norlin Music, Inc., the company that purchased Moog Music. I present them here along with some hopefully entertaining commentary.”
– J. Donald Tillman
Visit Moog Patents at www.till.com.
“It works okay, I guess.”
I’ve recently taken a detour from the alien world of circuit-bending into the greater cosmos of electronics. And what better thing is there to do with my new found hobby than to build modules for my Doepfer Modular? If you answered “why nothing,” you deserve a cookie.
Inside the box
Above you’ll see the result of my entire Saturday, the Shinola Low-Pass. It is a simple, passive knob-controllable low-pass filter. Its constructed from an old GBA-SP box, two capacitors, wire, two 3.5mm jacks and a 50k potentiometer.
It works okay, I guess. I intentionally crowded the jacks and pot into the corner, giving me room to expand it’s functionality later. The cutoff only goes so low, which could have been fixed with higher capacitance capacitors. Still, not bad for a first try. Despite being mostly useless, I’m quite proud of it.