My first synth schematic - comments & suggestions please

Discussion in 'The Projects Forum' started by rushton, Nov 22, 2009.

  1. rushton

    Thread Starter New Member

    Oct 13, 2009
    9
    0
    Hi All

    I've just drawn out my first schematic for a synth I want to build. It's loosely based on a few of Nicolas Collins' designs from his book and a few other bits and bobs I've picked up here and there like the Sleepdrone from kingcapitolpunishment and the drone lab from casper. I've only tested one oscillator on it's own at the moment and it works fine but it's not as smooth as I would like it.

    It's a relatively simple design and I've avoided the use of transistors as I'm not confident enough to throw them in yet but I would like to figure out where and how they could improve this. But aside from transistors, I am hoping you fine people out there can give me some general comments and suggestions. Please note I have only been doing electronics for about 8 weeks, so a semi-layman approach would be appreciated.

    Thanks
     
  2. gootee

    Senior Member

    Apr 24, 2007
    447
    50
    What do you mean by "not as smooth as I would like it"? Square and triangle waves will not sound "smooth" like a sine wave. Is that what you meant?

    But... if you low-pass filtered the triangle enough (or the square wave, for that matter), it would become almost a sine. The trouble there is that the low-pass filter's cutoff would have to be able to be changed, depending on the pitch. And you'd need several filter stages. Maybe you could just try adding a sine oscillator, or look up a better way to do a triangle-to-sine converter.
     
  3. rushton

    Thread Starter New Member

    Oct 13, 2009
    9
    0
    It was more when I adjusted the frequency with the tuning knobs the pitch would wobble sometimes. Not sure if this is down to the simplicity of the design or my shaky hands.
     
  4. gootee

    Senior Member

    Apr 24, 2007
    447
    50
    That's kind of interesting. It sounds like some temporary undershoots or overshoots somewhere, while things are changing; like imperfect tracking of something. Does it happen that way for both triangle and square waves, and with the range switch in either position? Maybe it's the large caps, not keeping up...
     
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