Behringer BSY600 CV/FCV100 footpedal modification and/or alternate control circuit

[Bloodbath]

I have a Behringer BSY600 Bass Synthesizer and I use the CV output on the FCV100 foot pedal for the expression pedal control voltage. I believe the expression pedal outputs a cv of 0-5v.
The settings I use on the BSY600 makes me constantly sweep the expression pedal and that kind of just sucks.
Is there a way to replace the pot with some sort of oscillator that would basically do the sweep for me?
Alternately is there a circuit I could build that would oscillate with a cv output so I don't have to have that big foot pedal? Obviously I would like a little control of the rate of oscillation.
I tried to figure this out looking at VCO circuits but I know very little about CV and am not even sure if that is what is needed. I'm guessing waveform might be a little important here also.

EDIT: Upon further inspection, the FCV100 doesn't supply the power for the CV. It is supplied by the BSY600. The FCV100 in CV mode is just a 50k pot controlling the CV via a stereo cable. What I THINK I need is some sort of oscillator to replace the 50k pot????????

[Jazz P Bass]

Sounds like a fun project
I can visualize it thusly.
-An adjustable frequency self running oscillator circuit that drives a class a transistor circuit.
-The collector varies the CV voltage from 0-5 volts.
What is needed is the CV circuit description.
I am not that well versed in the CV logic.
What is the pedal potentiometer doing?
Is it simply varying the 5 volts back to the CV circuit, which accepts it as an input?

[Bloodbath]

I verified that the only thing the foot pedal does is sweep from 0k to 48.2K using the ring and tip.
The EXP jack on the BSY600 gives off 3v on the ring and 3.27v on the tip. I didn't check if this voltage varies with different MODE settings. I just checked with it on MODE 1.
Here is how the jack is hooked up to the pot in the expression pedal. It also shows which voltage supplies are going through the cable.

[Jazz P Bass]

That helps, thanks.
Please be aware I am doing this as a mental exercise.
I am not about to design this circuit.
So...
You want to vary the Tip voltage & send it back to the Ring terminal.
An adjustable oscillator can be made using a number of devices.
A 555 timer, a Schmidt trigger, an opamp.
The class A circuit is pretty straight forward.
What I see as an issue is, you will need a separate power pin.
Being that the driver is class A, you need a little "headroom".
So the voltage source will have to be a little higher than 5 Vdc.
You cannot use the TIP voltage as a source.

[Bloodbath]

I just need to be pointed in the right direction. Basically, if I knew what kind of circuit I needed, I could figure the rest out. Knowing the expression pedal is only a pot and is just varying the CV supplied by the BSY600 just made it a lot easier for me (in my head anyway).
I kind of figured the oscillator would have to have it's own power source.
I am actually already working on an LFO for another project that uses a PIC and LDR. I'm wondering if that would work well in this situation. I just started that so I'm not really sure of the end product yet. I'm aiming for multiple waveforms so that could be interesting. I'm not too sure how the waveform is going to affect this application though. I've never tried anything like this before.

[Jazz P Bass]

It does not appear to be that difficult.
For me, the LFO is the hard part.
Google Class A circuits.
here is a nice tutorial:The Transistor Amplifier - Page 1

[Bloodbath]

I was thinking something as simple as this would work: Modulated Big Muff Tonestack using 2 LED/LDR combos and an LFO