Are there any pcb's out there, or mods to existing projects, for a envelope filter pedal switchable to be controlled by LFO? Like, maybe, is there a way to use the LFO in the sample/hold side of the sharkfin/maestro FSH-1 to modulate the filter side?
You could try this with the Meatball by pulling the LM1458, and running the LFO signal into the Intensity expression jack's tip (don't touch the sleeve, attach the LFO circuit's ground to the Meatball's ground. The sleeve for Intensity is not ground.) Run the LFO through an attenuator of some sort first and bring it up slowly -- the LED on the front normally used to show the Envelope should show what is going on. Disclaimer: not my fault if you kill it :P
you could always build robert henrys light wah, its fabulous
https://www.youtube.com/watch?v=CPhrmxm999Y
You can mod ANY envelope filter to do this. The envelope signal will feed into something that varies an LED or a transistor; just find that component, build an LFO to feed it, and use a switch to choose between the two things.
So like in the Kraken, you could build everything but leave the base of Q2 disconnected from the PCB, and run a piece of wire from the base to the center lug of your switch. One lug would connects to the base's connection on the PCB and that throw will connect the envelope. Build, say, the LFO from the Phase 45 or the Aquaboy and connect its output to the other outside lug of the switch and presto you've got an LFO.
Or do it with the Mutron III. Disconnect the LED anodes from pin 7 and switch them between pin 7 and the output of the tremulus lune's LFO.
Or take the Light Wah and build just the LFO part (leave off the manual control). Swap what feeds the transistor connected to the LED in that with the output of the envelope circuit of your choice.
thank you all for the suggestions! i have the mutron III and mistress boards, so i may try to get the lfo from the mistress to the mutron and the envelop from the mutron to the mistress rate or range. I'm getting a little better identifying the circuit features/sections with your advice, much appreciated.
mark
I've put an external LDR on a resonant filter (the BYOC fixed and envelope filter, one of my very first builds) and have controlled it with external LED with LFO. I have a board producing tap tempo LFO (including S&H) that I'm thinking of using to control an envelop filter - just haven't got to it yet...