Finished Pieces



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    10 Responses to “ModularSK1”

    • 1

      zealot said:
      January 12th, 2010 at 7:08pm #

      Hallo Casper,

      please could you explain, what the potis in the right section on the last photo exactly does? Are these pre-patched bends? And how did the big black stereo-potis on the right and left side works?

      Happy new year from germany!

    • 2

      casper said:
      February 18th, 2010 at 1:15am #

      This SK1 is totally modular. There are no pre set mods.
      The white patch points in the middle of the faceplate are connected to the audio synth chip. All of the switches and potentiometers on the faceplate are for patching and controlling points from the main patchbay. The BIG potentiometers are 10 turn pots. These allow you to make very fine adjustments.

    • 3

      tom said:
      April 14th, 2010 at 6:52pm #

      hey casper, i have been getting into circuit bending recently and have found your site to be very informative. i was just wondering what type of jacks you used on this mod. i am in the process of building something similar to this and was looking into using dc power jacks but it can get quite expensive. i was also wondering about the pitch mod on the sk1.. do i have to unscrew the board and solder the points from the other side? i have found the pitch base but i havent hooked it to the + and – power supply out of fear of destroying my sk1 which i have spent much time on recently. if you could answer any of these questions id really appreciate it thanks again man!

      also if you could point me in the right direction to finding some cheap jacks that would be awesome. i looked through the sites you recommend but i am not sure of what to order lol thanks

    • 4

      Pelham said:
      April 20th, 2010 at 8:10pm #

      Hi Casper,

      I am currently working on a concertmate 500 and would like to build my own patchbay similar to the one here. I have been looking into using rca jacks but haven’t been satisfied with what I’ve found. What kind of plugs are those green and yellow ones? Any advice on building a patchbay and what parts you would suggest?


    • 5

      casper said:
      May 1st, 2010 at 3:35pm #

      @ tom & Pelham:
      I use banana jacks. They are available in several colors
      and they are relatively cheap. I order them from This is the cheapest resource I’ve found for decent quality banana jacks. Here’s the link:

    • 6

      casper said:
      May 1st, 2010 at 3:38pm #

      @ tom:
      The pitch adjustment on the SK1 is very limited. I’m pretty sure the on board pitch control is an adjustable coil. I think you can get a wide pitch range by replacing the coil with a high frequency oscillator. sells a little timer kit here:

    • 7

      Jason Justce said:
      January 27th, 2011 at 8:37pm #

      Hi Casper, im a huuge fan of your work. my casio just stopped putting out sound. i desoldered all of my bend and made sure nothing was touching wrong areas. do you ow what the best thing to do would be? i would really appreciate it really sucks ;/

    • 8

      casper said:
      April 2nd, 2011 at 1:39pm #

      Hey Jason. Sorry for the late reply. Debugging a problem like this can be pretty involved. There are so many things that could have happened and theres no one approach to figure out what is wrong. It could just be broken. You already did the first step which is to undo the bends you already did and look for shorts. AT this point I enthusiastically encourage you to move on to the next project. Find another casio and make sure your process is organized and the work is clean. You can spend a lot of time trying to fix a dead keyboard. You are probably better off building a new one.

    • 9

      hammer said:
      July 9th, 2011 at 3:45pm #

      Always love your work, Casper. I’ve done a patchbay on another SK-1, but am planning a more complex version (not as complex as this modular, just patching through pots and building a pretty enclosure). May I ask what size pots you used/recommend (other than the 10 turn, that is) for the main patchbay? Keep up the beautiful work, my friend.

    • 10

      casper said:
      July 9th, 2011 at 4:12pm #

      Hey. thanks! I suggest small value pots. 100 ohms primarily. If you can find 200ohm pots I would use those as well. 500 ohms may be too much. I’ve found that most glitches have a sweet spot sweep of around 20 ohms. Its a bit odd but a lot of the glitches will have a window where they change… so for instance between 0 and 20 ohms it will crash, between 20-40 ohms it will glitch and the glitch will change as you increase the resistance. Above 40 ohms and the glitch turns off. That’s just an example, you’ll find lots of different scenarios.

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