About the Design

The Karplus Strong Modular Synthesizer board has the following subcircuits combined together to create an analog circuit version of the algorithm:


  1. -VCO with Expo Converter

  2. -VCF with Expo Converter

  3. -Jan’s Level Shifter

  4. -Summing Amp

  5. -Bucket Brigade Device

  6. -Output Amplifier

  7. -5 Volt Regulator


Karplus Strong is the name of an algorithm published in 1983, and named after the people who published it.  Their original concept was implemented as a digital chip and it has been recreated over the years in software and hardware form. 

I converted the algorithm into analog electronic form to create a modular synthesizer circuit board that offers a lot of great sound in a small and inexpensive module.  Team it up with your favorite sequencer to make great guitar, drum, and other sounds. 

What is Karplus Strong?


I would like to thank wmonk, Blue Hell, Dan Lavin, jeff-o, dugernaut, JovianPyx, yerpa58, DGTom, Uncle Krunkus, loss1234, electri-fire, rubendelacosta, mrcold, State Machine, mosc, bbob, rosch, and perhaps others for their participation in the design thread on the electro-music.com forum. 

Also many thanks to ChucK programmers who helped me understand the algorithm and of course thanks most of all to Karplus, Strong, and whoever else worked on the original algorithm. 


You can study the Karplus Strong circuit board design by reviewing the KS11sch.pdf, KS11pcb.pdf, and KS11bom.txt files - enjoy!