simple opamp low pass filter?

[freddd]

Hey there, I've been looking for a simple opamp based low pass filter for days but I just don't seem to be able to find a suitable scheme anywhere! I tried Tim's Quasi VCF's but they were too unstable. I'm basically attempting to create a super simple version of the moog low pass filter but am thus far - Stumped!

Any of you guys got ideas/schemes for sweepable low pass filters?

Cheers for any help!

[Paul Perry (Frostwave)]

Only the Moog ladder sounds EXACTLY like a Moog, but if you want a sweepable low pass, I can recommend the LM13700 based voltage cdontrolled low pass from the National Semiconductor data sheets. yeah, it has +-15V rails (!) in the data sheet, but it works on +-4.5 OK.

If only there was a simple version of the Moog low pass that actually sounded OK! I might add, that if you want your low pass filter to sound 'interesting', you might want to apply some resonance to put a peak in the response.