# Circuit bending Casio SA keyboard **URL:** \ **Category:** DIY STUFF\ **Created:** [May 8, 2020, 9:40pm UTC](https://lookmumnocomputer.discourse.group/t/circuit-bending-casio-sa-keyboard/846 "2020-05-08T21:40:26Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Piecho](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/piecho/32/1782_2.png) [@Piecho](https://lookmumnocomputer.discourse.group/u/Piecho)\ **Post date:** [May 8, 2020, 9:40pm UTC](https://lookmumnocomputer.discourse.group/t/circuit-bending-casio-sa-keyboard/846/1 "2020-05-08T21:40:26Z")
Hello, I have Casio SA 20 witch I want to use with my future eurorack. I want to make some mods according to the drawings([http://synthvibrations.com/tag/casio-sa/](http://synthvibrations.com/tag/casio-sa/)): [http://synthvibrations.com/wp-content/uploads/2010/08/SA-X.jpg](http://synthvibrations.com/wp-content/uploads/2010/08/SA-X.jpg) [http://synthvibrations.com/wp-content/uploads/2010/08/SA-Xbends.jpg](http://synthvibrations.com/wp-content/uploads/2010/08/SA-Xbends.jpg) [http://synthvibrations.com/wp-content/uploads/2010/08/Casio-SA-7-bend-diagram.jpg](http://synthvibrations.com/wp-content/uploads/2010/08/Casio-SA-7-bend-diagram.jpg) But I have one more idea - may I add input for external oscilator? I think just to add mono-jack input into the pitchshift line witch proper switch that will cut factory crystal. Is it so simple or do I need any normalization of signal before? Any other ideas for the mods, maybe adding some expression stuff like vibrato? But how : D ---
**Author:** ![Maxhirez](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/maxhirez/32/42_2.png) [@Maxhirez](https://lookmumnocomputer.discourse.group/u/Maxhirez)\ **Post date:** [May 9, 2020, 1:13am UTC](https://lookmumnocomputer.discourse.group/t/circuit-bending-casio-sa-keyboard/846/2 "2020-05-09T01:13:12Z")
Flagging @fredrik, @Dud and @antoine.pasde2 to get their attention for this (they’d be the experts for this.) I don’t think that you’d want to cut the crystal off though-chances are that’s more for controlling a microprocessor than for audio oscillation-but you might still be able to get glitchy with it-maybe that’s what you want. ---
**Author:** ![antoine.pasde2](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/antoine.pasde2/32/326_2.png) [@antoine.pasde2](https://lookmumnocomputer.discourse.group/u/antoine.pasde2)\ **Post date:** [May 9, 2020, 1:46am UTC](https://lookmumnocomputer.discourse.group/t/circuit-bending-casio-sa-keyboard/846/3 "2020-05-09T01:46:30Z")
I’m no circuit bending expert, but it looks like you need a clock in the 6 to 22MHz range, for the circuit to work reasonably. A direct external clock input at those frequencies might be a bit hard to obtain ( it could also cause interference to nearby radio equipment if connected with an un-shielded audio cable ). I think what circuit benders often do is to install a controllable high speed oscillator. Sam mentioned one a couple of times in his videos (maybe the LTC1799 with a vactrol for VC input?) I know I shouldn’t do this but I’ll point you to [this article](https://www.circuitbenders.co.uk/forsale/LTC/LTCguide1.html) that I haven’t read but seems to describe something you could use. ---
**Author:** ![d42kn355](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/d42kn355/32/273_2.png) [@d42kn355](https://lookmumnocomputer.discourse.group/u/d42kn355)\ **Post date:** [May 9, 2020, 3:30am UTC](https://lookmumnocomputer.discourse.group/t/circuit-bending-casio-sa-keyboard/846/4 "2020-05-09T03:30:55Z")
If it’s circuits is anything like an sk-1, LTC1799 is the way to go, as with most Casio Keyboards. I would imagine their crystal is similar, and with mine, I cut the original trace and routed it to the LTC with 2 switches, a pitch pot, and external jumpers. 😃 ---
**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\ **Post date:** [May 9, 2020, 9:17am UTC](https://lookmumnocomputer.discourse.group/t/circuit-bending-casio-sa-keyboard/846/5 "2020-05-09T09:17:00Z")
like all said LTC1799 is a good way ![LTC 1799 osc](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/9/9d4114fcdc76fce1f964bfc97e7aad09f76bd3af.jpeg) add maybe with a swith to select original cristal or LTC1799 ![insideview1](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/9/907fff4469b162d0bf5c7c8e29f1963c8497e792.jpeg) for tremolo/vibrato/LFO, a little 555 timer with a vactrol on the pitch pot (for internal LFO) or just a vactrol with maybe a pot (Attenuator) with a jack socket for external control ![lfo_vactrol](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/1/1afcea89efeaa8dd863e7562d73fc78c9f595420.jpeg) here’s mine SA38 [https://soundbender36.wordpress.com/category/casio-sa38/](https://soundbender36.wordpress.com/category/casio-sa38/) ---
**Author:** ![Piecho](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/piecho/32/1782_2.png) [@Piecho](https://lookmumnocomputer.discourse.group/u/Piecho)\ **Post date:** [May 9, 2020, 10:00am UTC](https://lookmumnocomputer.discourse.group/t/circuit-bending-casio-sa-keyboard/846/6 "2020-05-09T10:00:13Z")
Thanks! Still waiting for the LTC1799, will back to it then I will have all parts. Your SA looks mad, do you have any jamm records using your modular with this beast? For sure I will have some more detailed question when I will try to put mine together. I`m curious if there is any easy way to implement pot as an modulation knob for your LFO scheme, or maybe there is already some cheap pre-made parts for it. Like this springy one - ![](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/1/1318ec62a2060de5ebd07b84d848a1481db18194.jpeg) EDIT: Just found this springy thing in my basement. Need to figure out how the pinout is and if it is close to 10k - this as I assume it will fit into your LFO drawing? Or it will be more complicated? For the plastic part I can find someone with 3d printer and model it. [![Google Photos](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/0/072dd1f561acf04e719cd968f8901492f3a9a4bf.jpeg "New photo by Piecho3a") ](https://photos.google.com/share/AF1QipO4X_yDaOTQQ-qwwiJAxXqYRVdatJdzUQ6KayaUBh1VuDGkHCA-2it-hUqc71nn3Q?key=TVhZYnZUN01JQ0c4TDdRZ1ZGcjc2Tmt2em5lWU53) Forum cut the image - you gave to click it to see 5 pins. ---
**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\ **Post date:** [May 9, 2020, 10:44am UTC](https://lookmumnocomputer.discourse.group/t/circuit-bending-casio-sa-keyboard/846/7 "2020-05-09T10:44:38Z")
no i have no jam with it with my modular, i made a intern LFO with 555 but no external CV, so no controlable by an external signal … of course i think you can use any style of pot for this LFO circuit here is a better diagram for the 555 with Rate but in addition Shape and Depth pot ![yamaha pss mod LFO cristal reset ...](https://global.discourse-cdn.com/free1/uploads/lookmumnocomputer/original/2X/b/bf748696b45dfe600c4f4e68b298921b0c3a5280.jpeg) for your new pic, i seems to be a XLR connection, are you shure it’s a pot ?