Mod LFO in chorus pedal to get true vibrato

[gutsofgold]

Let's say I have an old beat up Boss CE-3 and never use the stereo output feature (one output full dry one output full wet). If I smooth out the LFO to a sine or pseudo-sine and only use the wet output in stereo mode, I'd be looking at true pitch shifting vibrato, right? Perhaps needing to change up the rate control to better suit the slower vibrato sound.

[gutsofgold]

And if this could potentially work (I just really want a VB-2 but can't justify the price for them on ebay)... is there any easier way to coerce a smoother more siney output from the CE-3 than to just copy and paste the VB-2s LFO into the CE-3?

[armdnrdy]

BYOC has a VB-2 clone kit:

http://buildyourownclone.com/analogvibrato.html

[gutsofgold]

Thank you for the heads up  I'm looking to do some hacking though 

[Mark Hammer]

1) Yes.  Where chorus is audible over a wide range of modulation rates, vibrato demands a somewhat faster sweep range in order to be audible.  The stock CE-3 has a 100k speed pot, with a 10k fixed resistor on the ground leg. Consider swapping that for a 47k/50k pot, with a 62k fixed resistor to ground.  That will give you the same range of faster speeds, and spread them out over a broader arc of adjustment, but eliminate the slowest speeds.

2) In the CE-3 schematic, you will see a 220k resistor labelled R45 after the Depth pot.  Consider splitting that resistor into 2 series resistors (e.g., 100k+120k), and running some sort of back-to-back diode complement from their junction to ground to "round off" the peaks of the triangle. 

[gutsofgold]

Interesting. I wonder if any of the more complex triangle to sine waveshaping options would work here. Something like the example circuit in the Falstad simulator. Just a large voltage divider network situated "under" a number of back to back diode stages such that each stage shapes only a portion of the triangle. Wonder if I can fit 12 diodes and 20 resistors in the CE-3.

[LaceSensor]

just buy the Behringer UV-300 and hack it into a 125b and be done with it (!)