Boing! Discrete Transistor Low Pass Gate

The Boing! is a Light Dependent Resistor-controlled low pass filter. It takes its primary inspiration from ultra-simple yet delightful passive Vactrol Low Pass Gate modules such as the PassiVac and DPLPG, but adds JFET transistor input and output stages and an active LED control circuit, thus enabling the introduction of wonderful Feedback and Trigger functions, LED brightness offset, and a second filter stage. Combined, these features allow for incredible variable-cutoff overdrive and low pass filter sounds in addition to bouncy LPG Bongos and more.

“Received the Boing & it's great! Figured I'd be using it for normal LPG stuff, but a big bonus is the huge range of voltage controlled overdrive sounds! Mild fattening to full-on gnarly brutality but always with a warm, natural, organic sense. A lower input signal softens it up while still having plenty of gain to compensate. It's my new secret weapon like this: 1vco > Boing! > vcf > vca. Gotta try it in front of the Marsupial or Macropod. Huge!” -Len R.

Current draw: 12mA @ +12V, 0mA @ -12V

Eurorack width/depth: 4hp; 28mm

4U width/depth: 1”; 28mm

4U / Eurorack User’s Manual

4U / Eurorack Build Manual

4U Bill of Materials

4U Interactive BOM

Eurorack Bill of Materials

Eurorack Interactive BOM

BOM changes since initial release:
R7 changed to 47k (was 10k) - increases input impedance
R19 changed to 4.7k (was 10k) - increases Hit! input sensitivity
RFB1, RCV2 can be B50k or B100k
updated 12/26/21