Escobedo's PWM and the Psycho LFO?

[Mr. Lime]

Tim Escobedo's PWM circuit is simple and sounds cool.
I would like to take use of the free schmitt triggers of the CD40106.
Ken Stone's Psycho LFO needs exact 4 so it fits the bill.

Has anyone experience with the Psycho LFO?
Single 9V supply would be needed.
How about switching 3 of the 4 inverter away to have access to a simple sqaurewave?
Is the glide cap able to form a pseudo triangle?

I haven't tried it yet but I guess there are better input gain stages instead of the 386D amp.
Maybe a comparator or zero crossing detector tracks the guitar signal better?




What are you guys thinking?

[Ben N]

I know what an LFO is, and I think I know more or less what a psycho is, but I have no idea what a psycho LFO is--is it kind of pseudo-randomizing LFO?

[Mr. Lime]

The Psycho LFO consists of 4 schmitt triggers. Each is set up differently and the square wave outputs of are summed in IC2A.
Only one has a variable resistance to control the frequency.

[duck_arse]

What are you guys thinking?

I'm thinking I'm interested in what you find.

[Ben N]

The Psycho LFO consists of 4 schmitt triggers. Each is set up differently and the square wave outputs of are summed in IC2A.
Only one has a variable resistance to control the frequency.

I see that, but I guess the question should be, to what end?

[anotherjim]

It recreates the random sample sample&hold effect found in synths. It's used as a control voltage source for VCO or VCF pitch control. It only changes in step with the LFO speed.  The Psycho doesn't have the timing regularity, both the timing and amplitude can appear to be random.

[blackieNYC]

I made a very simple Escobedo PWM with two blended Schmidt trigger oscillators at fixed frequencies.  Just to make it swirl around. It's great!
The switch to a single oscillator seems easy. Tie the outputs of three oscillators, the fourth always goes to the mixer, and the other three join the mix thru a switch.

[Mr. Lime]

I really have to bring this to the breadboard..

Having some 40106 laying round I'm thinking about adding another one to this PWM circuit.
With 4 40106 gates we can wire a XOR gate leaving us another 2 unused for a oscillator with PWM control again.
The XOR can be used as ring modulator feeding the previous PWM into on input an the new oscillator into the other.



Not sure about the duty cycle and frequency controls. I guess they will interact with each other but it might not hurt as much in this application.

[Mr. Lime]

Maybe that's the better oscillator for the XOR ring modulation:


This one offer's a polarity switch and no 40106 gates are left unused.

A blend control between pin 4 of the first 40106 and the XOR output to mix the signals should be considered to pan between square wave fuzz and ring mod..
I will do a final summary schematic for you guys which will be easier to understand and follow. 


EDIT:
I have a lot of 4046 laying around as well and I it might be easier to replace the second 40106 with one 4046 set up as an oscillator.
This would allow us to modulate the frequency with a CV. The Psycho LFO could then be used as CV source as well.
So the LFO can either modulate the PWM of the fuzz or the frequency of the ring mod.
It's probably unnecssary to have PWM controls for both signals going into the XOR gate.