Anyone know anything about Synth circuits?

[Madferret]

I've been asked to build a simple oscillator by an artist who wants to build it into a sculpture. The brief is to have a sine/square wave that  will change frequency from around 0hz to 100(ish)hz and back every 20 seconds. I built a prototype that worked but I've found it hard to get as low as 0hz and it's not producing a very clean sine wave so there are a few harmonics in there.  I know it's not really an effect related question but it's been a fairly interesting project so I wondered if anyone had anything that might help me out?

[otalgiafx]

XR-2206 maybe, though I think that goes down to 1hz

[Madferret]

Thanks mate, that's actually opened up another avenue, much appreciated.

[otalgiafx]

No probs, hope it works out.

Maybe you can help me? I've had 2 goes at building the Dwarcraft robot and on both builds I have had the dreaded helicopter clock sound, I tried skipping the starve control but still get that annoying clicking, can you remember how you cured your build (or does it still click?), cheers

Mike

[Madferret]

To be honest I ended up giving the one I built to a friend so it's been a while since I played with one. I did mainly use it with the tone rolled back to give the really deep 8 bit octave down sound which could have cut out some of the click. You could try adding a small (220r?) resistor in line with the 9v in, especially if you've ditched the starve pot, also a 47uf filter cap between the 9v/starve 2 row and ground might help but it could also affect the sound.

[otalgiafx]

Thanks, will give your suggestions a try, have a good weekend.