Finished Pieces

Modular Benjolin

    This is my take on Rob Hordijk’s amazing Benjolin synthesizer. In Early 2010 I started working with Brendan Gaffney of BurnHeart Synthesis. One of the big projects we’ve been working on is adapting the Benjolin into a fully modular system.

    Here’s three modular Benjolins blippin away

    Here’s a video showing the first prototype of the current modular Benjolin design. You can also see modular benjolin version 1 in the top left corner of the screen.

    Makin’ it modular:

    It was important to us in adapting the Benjolin to make sure it retained all of the original functionality that Rob designed into it. We also wanted to greatly extend its capacity to interface with other gear, especially other Benjolins. So, while it is completely modular we decided to include the normalized features of the original, like “rungle amount” for the oscillators and filter and put in switches on the rungle section to switch between the original setting or external inputs.
    Here’s a list of all the features, old and new.

    FEATURES: (** indicates original feature. All others features have been added to the modular version)
    (2) VCOs
    —Coarse tune adjustment**
    —Fine tune adjustment
    —Rate indication LED
    —Rungle amount adjustment**
    —– square and triangle output jacks**
    —– 2 frequency CV inputs w/ adjustments

    (1) VCF
    —Cutoff adjustment**
    —Resonance adjustment**
    —Rungle amount adjustment**
    —Internal mix level adjustment
    —–2 cuttoff CV inputs w/ adjustments
    —–2 audio inputs w/ adjustments

    (1) Rungler
    —–Clock input jack w/ clock select switch
    —–XOR input jack w/ OSC/loop select switch (see Rungle mods below for more details)
    —–3 bit output jacks w/ state indication LEDs
    —–Rungle output jack **
    —–XOR output jack **

    (2) AR envelope generators
    —Attack rate adjustment
    —Decay rate adjustment
    —State indication LED
    —–Gate input jack
    —–Envelope output jack


    Click the schematics below for more info






    Sorry, no sound files for this piece.

    29 Responses to “Modular Benjolin”

    • 1

      Mr James said:
      August 4th, 2011 at 2:02pm #

      That’s one F**k of a job you’ve done there, if you don’t mind me saying!
      So Rhythmic, such original sounds and the fact that its all CV sync-able,is just the cherry on top.
      Thanks for putting these schematics up, the different circuits look like they’ll be useful for many projects. The CV section alone, is vastly usable. Brilliant!
      Is there anything in the pipeline in the way of a kit for sale for this Beauty?! It would make XMas!

    • 2

      Giancarlo Sica said:
      August 20th, 2011 at 4:25pm #

      Hi there…
      How do you do? I trust as well!
      Great idea the Modular Benjolin!
      Do you have any plans to realize a PCB (and/or a kit) for this excellent project as you did for the Drone Lab?
      Please let me know!
      Best regards, G.

    • 3

      casper said:
      September 2nd, 2011 at 5:22pm #

      I am in the very beginning stages of making a mighty benjolin PCB with Rob himself. I’m crossing my fingers that it will all come together in a timely fashion.

    • 4

      casper said:
      September 2nd, 2011 at 5:32pm #

      @Mr James.
      All of the brilliance in this piece is from Rob Hordijk. He’s a clever man. There are plans for a kit but not by christmas.

    • 5

      jean bender said:
      February 14th, 2012 at 1:25pm #

      Hi Peter !!
      Thanks for your work… still amazing…
      As on electro music forum, i don’t understand one part of the schematic : what is J2 / HDR16… Lots of 100k resistances there.. but i don”t understand how to wire it to the other parts…
      Thanks for helping me troubleshooting that !
      cheers !

    • 6

      casper said:
      February 16th, 2012 at 9:18pm #

      Hi Jean!!
      Ahh. J2/HDR16. Thats where all the magic is! Those are all of the outputs of the discrete wave forms that make up the benjolin. You can use these to patch into other gear as control signals or audio signals or patch them into the VCO&VCF CV inputs. This is the key to unleashing the monster.
      (I’m finally working with rob on a new upgraded bejolin PCB and kit. This one includes an echo! I’m hoping to have it done and in my store by this summer. Wish me luck!)

    • 7

      jean bender said:
      February 17th, 2012 at 6:51am #

      Yes ! Thanks Peter !
      So, i understand well, i can use there jacks… It’s only outputs ?
      Hope you’ll make it real… I’ve personnaly found some ics, so i think i’ll breadboard mine soon.. But i’ll be happy to get you kit, and… why not invite you & Rob in france for a workshop ??
      We keep in touch !

    • 8

      casper said:
      March 4th, 2012 at 10:27pm #

      They are only outputs. There are inputs elsewhere on the board. The VCOs and the VCF all have voltage inputs. You can use the outputs from HDR16 to control them or you can use another benjolin. Two benjolins together is a great combination!

    • 9

      Jean Bender said:
      March 8th, 2012 at 10:18pm #

      Hi Peter ! I was wondering what was the “ag” or A ground ? How is it built ? Is it a really important thing ?
      I don’t really see the difference btw gnd & agnd, since all the schematic seems to need AGND….
      thanks !

    • 10

      Matt Hill said:
      April 30th, 2012 at 12:07pm #

      Wait what? Kit? i would sell my internal organs for such a kit. What wonderful news! would you be able to give us an estimate on a release date?

    • 11

      casper said:
      May 1st, 2012 at 2:31am #

      @ Matt.
      I’m working on it. Hoping to get a prototype PCB designed and built by the end of the summer.

    • 12

      Matt Hill said:
      May 4th, 2012 at 12:02pm #

      Apologies, i should have read the above comments more thoroughly. The benjolin really stands out from the other synths IMHO and for those of us who cant get to a workshop this is brilliant news. I wish you all the best with it.

    • 13

      Kab said:
      May 19th, 2012 at 7:06pm #

      I really would like to implement that VCO indication LED, but I can’t see the chematics for doing it, can you help? 🙂
      Thanks a lot!!!

    • 14

      johnmcm said:
      December 3rd, 2012 at 7:38am #

      Is there any sign of a PCB for the modular benjolin. Or has it been
      buried under other projects?

    • 15

      Ludwig said:
      December 18th, 2012 at 5:16pm #

      Oh WOW! I just stumbled over this? Will there ever be a modular kit? Seems too cool to be true sadly.
      Maybe is there a possibility for a Vero/Perf Layout if the kit is not making it through?

    • 16

      Pfaffenberg said:
      January 3rd, 2013 at 12:20am #

      Kit! Paaaaaleeeeease!! Pretty please. 🙂

    • 17

      casper said:
      January 13th, 2013 at 5:52pm #

      slowly but surely

    • 18

      Joseph said:
      October 25th, 2013 at 3:40pm #

      The links for the schematics are broken. Did they get moved somewhere else?

    • 19

      Vince Zoras said:
      October 28th, 2013 at 3:04pm #

      Wow that seems to be alot of work but it is nicely build with little errors in the circuitry. Would require a weekend for me to play with.

    • 20

      sg said:
      February 1st, 2014 at 1:17am #

      This looks really awesome. I’d been toying with the idea of finding someone to etch a couple benjolin boards for me, but I think I’ll just wait for this one. I like it! (fingers crossed it’s still going to happen)

    • 21

      Lb said:
      February 3rd, 2014 at 12:11am #

      i’m patiently waiting for a kit too or maybe just the PCB.. Any news on this?

    • 22

      casper said:
      February 3rd, 2014 at 6:47am #

      Hey guys. concerning the benjolin module. Here it is. It was produced by Epoch modular:

    • 23

      sg said:
      February 3rd, 2014 at 10:42pm #

      No PCB then? :-\ That’s a drag. Etching it is then.

    • 24

      Leandro said:
      February 5th, 2014 at 1:34am #

      Thanks, but already knew about that module, what i´m really waiting is something from you.. so i´m etching my pcb.
      If you came out with something later just let us know.

    • 25

      Leandro said:
      February 5th, 2014 at 1:51am #

      Maybe can you help me in wire some led´s to show Rungler state or something else? Just want blinking lights! 🙂
      Correct me if i´m wrong but to wire three led´s out of 4021B pin´s 2/3/12 will need these:

      3x 1n3904
      3x 1k resistor
      3x 10k resistor

      Thanks in andvance

    • 26

      casper said:
      February 5th, 2014 at 8:15pm #

      Hey Leandro. Youve got the right idea.

    • 27

      Rex said:
      March 18th, 2014 at 9:36pm #

      Is that white material under the knobs used for shielding? ..It does keep it very organized.

    • 28

      Simon Smith said:
      April 9th, 2014 at 10:36am #

      Hi Casper, I met you the other week in Manchester at the Benjolin Workshop. It was a great day and I am now thinking about implementing some of the mods. As I am just finding my way with this sort of thing I was wondering if you could clarify something for me.

      1/ Is the pot for the audio input Log. Also are the other CV input pots Linear?

      2/ Is the 3 position SPDT switch on-off-on or on-on-on if it is the latter where do you get them from???

      I think I have all the other parts now and I will start putting it together in the coming weeks.Hope you are well, and remember you are welcome to DMU any time you are around. Best

      Simon (friend of John Richards)

    • 29

      warning said:
      February 2nd, 2015 at 12:43am #

      @ simon

      1) you can try and choose the one you prefer

      2) from the rungle mods page (, by looking at the schematic + this sentence in the loop mod section: “NO input = 8 step loop”, you can see that you need is a ON-OFF-ON

      You probably have figured out by this time I guess, hope it can help others!

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