I've built a few John Hollis Easy Vibe circuits and they've worked very well.
I found the R.G. Keen ramp mod, and attempted to implement it, with no success. Tried twice, and failed both times.
I can see that the output voltage to the base of the 2N3904 does ramp up and down, but I have no LFO. The LED's remain at a constant voltage.
So, I am not sure if I put the "Ramp Mod" in the circuit properly, or, if my use of TL064's could be the issue.
The attached schematic also has some extra stuff for a relay controlled switching, which is not part of the audio circuit. Just wanted to mention that.
Hoping someone here can take a look and tell me where I've gone wrong.
Thanks in advance to those smarter than me!
(https://i.postimg.cc/MXJDVm1X/Ramp-Mod-Vibe-Pedal.png) (https://postimg.cc/MXJDVm1X)
(https://i.postimg.cc/T52wDFPm/ramp-lfo-7.png) (https://postimg.cc/T52wDFPm)
R.G.'s notes say the opamps must be able to go to -Vcc. from what I can figure from the datasheet, that rules out the TL0xx.