Requesting more information on sawtooth wave pedal

[Esppse]

Hey I just stumbled on this video here:

https://m.youtube.com/watch?v=ljsDBvsxFm4

I was unable to locate the schematics used for this. Does a none here have any information on how the circuit can be built? No clue where to start with this

Thanks

(I didn't mean to double post, I posted in the schematic sub forum by accident)

[BluffChill]

Interesting - looks like one of your usual guitar to squarewave circuits, such as the Escobedo PWM



or one of parasitstudio's various brilliant guitar synth boxes https://www.parasitstudio.se/original-effects.html

But I'm guessing the output from the square is going to some sort of integrator to turn it into a saw, something along the lines of



Sounds really nice though - especially with the envelope. Shame he doesn't go into many specifics.

[Kipper4]

In the video he mentions the Schumann PLL.

A synths type thing?
I didn't watch much of it.


Hope it helps.
Maybe type Schumann PPL in a you tube search and see if it adds up.

Laters
Rich

[BluffChill]

Et voila!

Wow, it's huge.

[Esppse]

I have a PLL clone, it actually doesn't get that sawtooth wave because the one in the video has the square to sawtooth converter. Mmmm, I've never heard of any pedal like this, most use square waves. I'd love to be able to get one working and a verified Vero board layout to come out of this thread. I've built some Parasit stuff, an Xorcist, eagle claw, corruptor, theremin fuzz, and 8 bitar. All very awesome. I'd like the sawtooth tone now hehe.

[anotherjim]

The easy way to get saw wave is simply to high pass filter (differentiate) a square - but it has limited range, barely 2 octaves.

Narrow Pulse or PWM kept on the thin side can sound close without looking anything like a saw wave.

If a PLL is used, it can be set to run at a high multiple of the input frequency and clock a counter. The count outputs feed a resistor network that generates a "staircase" saw wave which after a little low pass filtering can be a pretty good looking saw. Trouble is, getting the PLL to track guitar reliably is not easy.

Again, a PLL that is tracking the input frequency has a VCO control voltage that is proportional to the input frequency. That CV could be used to control a ramp generator so the VCO square wave output could be shaped to a sawtooth over a reasonable range.