Adding delay control to MN3007-based chorus?

[sircletus]

Forgive me if my post seems a bit disjointed; I'm watching The Colbert Report.  Slightly distracting.  Anyway, I know I can control the delay time in my MN3007-based chorus pedal by changing a cap value on the CD4047.  My question is this:  How can I make a continuously-variable delay control a la the Visual Sound Liquid Chorus?  I've considered using a rotary-type switch to switch various cap values in and out of the circuit, but a potentiometer control would be so much smoother.  Ideas?

Thanks!
SirC

[Dirk_Hendrik]

I'd say studying this should help:
http://www.freeinfosociety.com/electronics/schematics/audio/ibanezsc10.pdf

[sircletus]

I love the FIS!  Thanks for the hint, Dirk!

[Mark Hammer]

Conceptually, what it is is a DC voltage summed with whatever the LFO voltage is.

A couple of caveats:

• This will not extend the delay range of the 3007, but will merely let you move around the range of clock speeds the current clock cap permits.  That may be all you really want, but I'm just letting you know that you won't be able to dial in huge leaps in delay time that can straddle the difference between, say, flanging and ultra-thick Pat Metheny-style doubling.
• The way circuits like the one linked to, and a variety of other commercial products, function is that the total range of "acceptable" control voltages feeding the MN3101 is divided up between LFO and Manual.  You will note that the Depth control is essentially set up like a blend/mix pot.  As you increase LFO Depth, you automatically reduce the degree of influence the Manual control has.  Being able to move around the overall delay range requires you to sacrifice sweep width by turning down the Depth pot.  That's not such a bad deal for faster speeds, since people generally like modest sweep width at faster speeds, buyt if the plan is to be able to achieve slow wide sweeps that begin and end at different points set by the Manual control, you'll have very little latitude.
      Of course, the big question is "Why do it this way?".  Simple.  The CV going to the clock chip can never be more than a certain value, and you need to make sure the LFO+Manual control voltage never exceeds that maximum.

[KB]

Hi sorry for late reply

If you go to tonpad and look at the build reports for the Smallclone project there are two build reports submitted by "henry" and the one by Chico

These outline what I think you are after doing.  The resistor to look at on the Smallclone schematic is R39, but they suggests some cap mods as well.

cheers

Kevin