i've looked at various circuits and they look simple enough to build.
however what is in my head is far more complex.... i might as well get it from the horses mouth through you guys - this is what i want:
i'm being greedy with an lfo circuit. i want it to produce a sine/tri/saw/square 0.05 to about 50hz... but i'd also like a "random" lfo, this is important.
i also want...and i guess this is the tricky bit. a 2nd lfo to modulate the amount of freq of the first lfo... this can produce really nice modulation... but i find more useful if a random lfo modulates a sine lfo's frequency.
this is easy enough to do with software... i used bidule for a tremolo like fx http://www.myspace.com/vlormusic/music/songs/maybe-you-should-chew-on-my-fist-74685079 the best example is this record.. the stuttered guitar pad that zips in and out is this very fx. (starts about 1:50mins in)
any help would be appreciated
This does 99% of what you're asking, apart from the maximum rate being 12.8Hz. Multiple waveforms, including random. It's also voltage controlled, so you can use another (slower) LFO to modulate the rate.
http://www.electricdruid.net/index.php?page=projects.lfo9
Probably the simplest way to go. To do all this in the analogue domain is a seriously big circuit.
Thanks for the link. I've delve into that. Looks interesting.
My initial thought re an analogue circuit was to sub a pot that controls frequency with a fet being driven from the output of another lfo.
LM13700 can make for cool VCLFO.
I'm all ears
There are quite a few circuits for LFOs at geofex. Some examples:
http://www.geofex.com/article_folders/lfos/psuedorandom.htm#Driving%20Effects%20Circuits%20with%20the%20LFO%20Waveforms (http://www.geofex.com/article_folders/lfos/psuedorandom.htm#Driving%20Effects%20Circuits%20with%20the%20LFO%20Waveforms)
http://www.geofex.com/FX_images/ramp-lfo.pdf (http://www.geofex.com/FX_images/ramp-lfo.pdf)