Switched-cap filter notes (link)

[Paul Perry (Frostwave)]

http://mysite.wanadoo-members.co.uk/tstinchcombe/synth/mf10/mf10.html
Tim Stinchcombe's experiments with the MF10.
possibly useful to us stompboxers, is his voltage controlled 4046 clock oscillator (think BBD). Nice1, Tim!

[George Giblet]

Something which is almost always missed on the switch cap filters is the need for input and output filters (like BBD chips):
http://pdfserv.maxim-ic.com/en/an/AN3494.pdf

[Paul Perry (Frostwave)]

Right you are George. I can't see the switched cap filters being much use for us here (except as a tracking filter to pull out BBD clock noise). I only posted the link for the 4046 voltage cdontrolled oscillator.

[gez]

I messed about with filters using that chip and gave up in the end.  To get any sort of range you need to clock the thing so low you end up with a pretty noisy circuit.  Plus, by the time you've factored in all the support circuitry (the filters, as mentioned) you don't necessarily end up with a circuit with a low parts count.