Boss VB-2 LFO not LFO-ing

[ConnorRMoore99]

Hi All,

On the breadboard today is an analog vibrato I'm working on based on a Small Clone. My plan is to replace the triangle wave LFO with the sine wave LFO from the venerable VB-2.

This circuit works great with the small clone LFO, but once I swap it with the VB-2 LFO it cuts out signal, which I assume is because it's not getting the CD4047 going, in turn not clocking the Mn3007.

Not too sure where to start about getting this going so any help is appreciated! Bellow are the schematics I'm using.

[ConnorRMoore99]

I forgot to mention that I only built the portion of the VB-2 LFO up to VR2, the depth pot, and I'm tapping my LFO output from pin 2 Of VR2. I didn't build any of the ramp circuit using the BA662a, maybe that has something to do with it?

[ElectricDruid]

Have you got a schematic for the VB-2 LFO, please?

When I played with the Small Clone clock, swapping the LFO like you'Ve done (for StompLFO in my case), I found it was very sensitive to the values of the 10uF cap and 39K resistor.

[amptramp]

As soon as you set the 10K depth pot in the second schematic to maximum value, the IC2a integrator stage is loaded down by the 10µF capacitor.  Most op amps would not be able to drive into that load.  If you only get failure to oscillate at higher depth settings, this may be the reason.

[ConnorRMoore99]

Thanks for your reply's! Here's a schem of the VB-2 LFO by itself. I hadn't thought to change the values of that cap/resistor so I'll give that a shot when I get home this evening!