Finished Pieces


The Benjolin is a relatively simple but wonderfully clever analog, complex sound generator designed by synth pioneer Rob Hordijk.

Here’s what Rob has to say about it on his website.
“The Benjolin is a ‘noise box’ that is ‘bent by design’, meaning that it always has a definite amount of unpredictability while it is still intuitive to play. The Benjolin features two eighteen-octave range voltage controlled oscillators that drive a ‘rungler’ circuit, circuitry that in essence uses a special interference technique feeding back into the oscillators to force them into wild chaotic behaviour.
A special slightly chaotic filter is both excited and modulated by the signals from the rungler circuitry processes, producing sounds between fat drones to grungy noise havoc.”


Here’s all the info that Rob has put online about building your own Benjolin:
*Benjolin forum*
*PCB parts layout*
*Parts list*

Here’s a slightly modified version of the schematic I put together.
New Schematic
The original version (linked above) is spread over 4 pages. I’ve consolidated it to one page and made a few changes to the labeling in order to make it easier for myself to read.

I’ve been working with the Benjolin a whole lot over the past year or so. See the links at the top of the page for some of the pieces I’ve built around this awesome circuit. I’ve listed a few modifications and additions worth checking out if you are considering building your own.
The mods can be found here.


Sorry, no sound files for this piece.

5 Responses to “Benjolin”

  • 1

    Jon Raskin said:
    August 28th, 2012 at 1:37pm #

    I’m very interested in the Benjolin kit when you have it ready. I’m a Blippo Box user and a fan of Rob’s work.

  • 2

    * Casper Electronics » Archive » Groningen Maker Faire said:
    January 26th, 2013 at 6:32pm #

    […] be demo-ing the NovaDrone and will have a few kits for sale. I’m sharing a table with Benjolin inventor Rob Hordijk. He’s bringing an epic modular system to try out. […]

  • 3

    Matt said:
    July 14th, 2015 at 4:13pm #

    Is there a more detailed part list out there? I emailled a whole bunch of component stores about it and they all said they need more specific information in order to put together an order (what wattage/ohm the resistors should be etc). I have the PCB and I know I need to get a clone for one chip but everything else seems to confuse them when I ask.

  • 4

    casper said:
    July 14th, 2015 at 5:05pm #

    @Matt. resistors can be around 1/4watt but if they’re above or below (1/2Watt, 1/8watt) it doesn’t matter. The most common resistors have a tolerance of 5%. you can use 1% if you want although there will likely not be any real difference. There aren’t any polarized capacitors so cap voltage ratings aren’t really an issue.. small value (non polarized) caps usually have a high voltage rating far above the power supply of the benjolin.

  • 5

    Matt said:
    July 14th, 2015 at 5:21pm #

    Thanks so much for your help!!

Leave a Reply

If you're not already logged in, there might be a question you need to answer before you post to prove you're human. It's there to help stop comment spam.