How do get extended range from Schmitt Dual Op-amp LFO?

[bartimaeus]

So I see those dual op-amp LFOs in a lot of pedals, from BOSS to boutique. It's a simple design and lets you waveshape pretty easily. But the rate range is limited in most pedals, and a lot of folks seem to use a switch to select between different LFO ranges.

Does anyone know any tricks to get a wider range of LFO rates from a single knob? I've considered using lower values for the resistors (and increasing the cap size to match), so the rate pot has a greater influence in proportion to them? But I also seem to run into some oddities if I make them too small... Any thoughts would be appreciated!



Here's a common implementation with some mods by fish boy:
https://fishboytech.tumblr.com/post/138814143993/modding-the-utility-lfo

[PRR]

With the Shape pot and diodes in the middle, you can't turn Speed down much and still have the >0.5V needed to turn on the diodes.

Also with 500k Shape pot making variable resistnce added to the 10k integrating resistor the speed and shape will interact a lot.

I suspect to get all these features and wide range you need a different design.