Pseudo sine wave good for general use or Drum kits.

[gibrancurtiss]

Hi guys

Made this little circuit to use with drum kits.
It's good from ~ 50hz to 200hz.
Pot 35 : Frequency
Pots 36 and 37 are to shape the wave the way you like. Or replace with trimpots to use a fixed shape.

If you want to crazy shape : I add a PWM diodes/pot on 40106...the wave gets cool.

Supply 9V + GND


I hope it should be useful for someone.

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[gibrancurtiss]

Here is a little better circuit.
Improvements from previous version:
-more stable and symmetrical;
-cleaner sound ;
-smaller circuit;
-wider range frequency.

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[PHOBoS]

nice little circuit, I am wondering what C62 does.
You could probably make an oscillator using 2 of the 4069 gates so you can do it with one chip.
An oscillator build with 2 inverters is also mores stable than a single schmitt trigger inverter one.
But if it will work might depend a bit on C62 since I assume the used 4069 is unbuffered.

[gibrancurtiss]

Hi Phobos

Thank you for your thoughts.

[PHOBoS]

I was thinking about this circuit, but I see now it has the capacitor on the output so that wouldn't work for your circuit.

I don't know what the waveform on the other side of the cap looks though.

There is also this one which uses 3 gates but might be useful.


even if you would need 4 gates for it you could still do it with 1 chip.

[gibrancurtiss]

Hi Phobos.

Thank you again.
No problem if the last capacitor must be removed.
I'll try both circuits tomorrow!

[PHOBoS]

The output of that first circuit is a squarewave. I thought the capacitor was at a different location so you could tap it
to get a triangle wave as with the 40106 oscillator, but that obviously doesn't work. As a I said I don't know how the
other side of the capacitor looks though, so maybe it is useful afterall.

[gibrancurtiss]

Hi Phobos.

You were right.
I checked the circuit and started it again.
I finished it with this little one.
The final wave is a triangular but with a good rounded edges .
I liked the final sound !
Now the bandwidth is all the way from a few Hz (40 maybe) up to a fine whistle.

With this configuration, we can do 6 oscs with one 40106 and one 4069.

Thank you !

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