microcontroller LFO to tremolo without LED/LDR?

[Pete.M]

Hi, I'm pretty new to the forum and new to effects building. I've got a modded-out Rangemaster clone with a 2n2222 in it finished that I like, and a muff clone that I'm not too fond of finished so far.

My next project is a tremolo with a micro-controller based LFO that can put out different wave forms (sine, square, triangle) to drive the audio stage. I've been looking at every trem. schematic I can find trying to come up with a way to get around using an led/ldr pair. My somewhat limited electronics knowledge leads me to think that driving a JFET (like an MPF102) with the 0-5v signal would work similar to the led/ldr "pot". Has anyone tried this or have any suggestions?

Thanks!
pete.m

[Pete.M]

Looks like I may have found what I needed in the "Piculus Lune". http://www.diystompboxes.com/smfforum/index.php?topic=77471.0.

I know, search first, ask later 

pete

[EATyourGuitar]

what you linked is another example using an LED/LDR. if your trying to do something without an LDR, you should search for a VCA circuit over on electro-music forum or google. try to find one that works on a single 9v supply or you could split your 9v supply to 9v/4.5v/0v with 4.5v virtual ground. google single supply opamp schematic. I think a LDR is perfect for a pic though since the response of an LDR will slew the digital stepping you get from a pic.

[lowbrow]

Would that not be a variation of the Wobbletron?

[Gurner]

Personally, if the LFO 'control data' is being generated by an MCU, I'd go the way of a 256 step (minimum) log digipot    .....feed the audio signal in to the digipot, feed the MCU control data to the digipot's control pins - job done.