Noise Machine VCA

I’ve finally received the joystick and it’s a bit of let down. They’re really intented for µC use, only the wipper is available (the other pins are connected to ground/VCC). The “breakboard” they’re coming with isn’t well designed and the upper screw will be on the way of one the axis. Besides, but minor, they return into their neutral place once released.

meCekoCfLXMUAOP0X87AaBQSo, two options. I do with that or try to find another one. It’s actually my fault I should have think a bit more but I couldn’t find cheap one without breakboard and such. Other than that,  they’re nice piece of kit if you want them for the primary application, that’s crazy what you can buy for few euros.

VCA stuff now.

I’ve tried few options for it. I wanted something easy to build and without trimmering (boring), something easily reproductible. I tried a jfet circuit, it worked good but needed trimmering and the Drain/Source path never really closed (let some sound go out). Not good enough. Out of despair, I tried the opto-coupler although I knew that this won’t do. The opto-coupler is really slow for the application and I want that VCA to do some ring-mod stuff with audio-frenquency modulation.

So I decided to try the usual diff amp as the Yusynth VCA I built for the Pico_Synth. Works good ! I modified it for obvious reasons (simple power supply). It Works pretty well and can go really high without issue. I like it !

noise_vca_jpgIMG_1338

The circuit ends up with more components that I wished but yeah…it’s more fun. There’re no doubts that a manufacter won’t bother with that and stick an OTA ( I understand and I’d probably do the same).

Now I should be concerned about signal amplitudes. Those are almost 4VP-P and no way I’ll get a clean output from the LM386 with such (with a 9V battery). I think the mixer will reduce the amplitude as well.

I’m still waiting for some crap to land to finish it but it’s gonna be a nice little annoying box, the cats will love it !

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2 Comments

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2 responses to “Noise Machine VCA

  1. Andrew

    I know this is bit of an old post but thought you might be interested to know…
    I wanted a couple of joysticks of a project and could not find anything suitable. In the end I went on to Ebay and got a vintage Radio Controller for about £7.50 (The type used to control model airplanes ‘Futaba FP-T5LGK’ ) and managed to salvage both joysticks. I have not used them yet but they look promising.

    • hi andrew,

      I had a look in google image with the reference you mentioned. Could be very fun indeed !

      I’m not really keen on those I have at the moment (with their middle off position). I have some size constraints but maybe I could find something like this. thanks !

      this project was put away with the entrance of modular synth but I’ll get back on it. I decided to finish things now !

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