Trillium waveshaper

phobos · Last edited by phobos on Sat Jun 06, 2020 3:18 pm; edited 1 time in total

After watching this video on how to make a window comparator with a single opamp
I messed around with the circuit a bit and turned it into a simple waveshaper.

I've only tested it with a triangle wave but you could use it with some other waveshapes (squarewave doesn't work of course).
note that the output signal is more rounded than drawn caused by the soft clipping of the zener diodes.

Trillium waveshaper.gif

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phobos · Posted: Sat Jun 06, 2020 2:57 pm Post subject:

and a demo

manual CV sweeping 0V..-5V..0V..+5V..0V
adding (triangle) modulation
increasing modulation frequency
changing oscillator frequency
(decreasing modulation to change to audio rate)
adding audio rate modulation
changing oscillator frequency
morphing modulation waveshape from triangle to square
changing oscillator frequency

PHOBoS - Trillium waveshaper demo.mp3

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PHOBoS - Trillium waveshaper demo

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blue hell · Posted: Sat Jun 06, 2020 4:01 pm Post subject:

Hmm .. boslelie .. bier ook .. cooledit was syntrillium ... it definitely has something with three as well .. nice idea, there was something with odd harmonics and up/downgoing pulses IIRC?

Edit: sounds nice too :-)

phobos · Posted: Sat Jun 06, 2020 5:23 pm Post subject:

AlanP · Posted: Sat Jun 06, 2020 10:51 pm Post subject:

I wonder... you mention soft clipping, would putting germanium diodes in series with the zeners have any effect?

phobos · Posted: Sun Jun 07, 2020 4:48 am Post subject:

gabbagabi · Posted: Wed Jun 10, 2020 11:00 am Post subject:

Hi!

The Trillium Circuit reminded me of something i had in the simulation-storage.

And with phoBos permission Smile

i post it here.

I have used the moment also to test the idea on my breadboard and it do work as simulated.

the basic circuit:

Fenster Komparator.png

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phobos · Posted: Sat Jun 13, 2020 6:52 am Post subject:

That's very similar indeed Laughing

Looks like you used a somewhat more conventional approach which is closer to what I would have done too
if I wanted to design a circuit to create that waveshape without having seen the single opamp window comparator.
Note that I started with my design with the idea that you could make the waveshaper with only a single opamp, a bridge rectifier
and 3 resistors. That worked but then of course came the idea to add some CV control to it to make it more interesting.

I wanted to do some calculations to see how it works but decided to breadboard it and do some measurements instead
which confirmed a small 'problem' with it. I think it's mostly because my supply isn't completely symmertrical but I believe
that the output of a TL074 (which I tested with) isn't exactly symmetrical either. As a result the output also isn't symmetrical
but this can easily be fixed by adjusting the resistor values of the final summing amp.

Apart from that I can confirm that it works and does exactly the same thing as the Trillian circuit, nice! Very Happy

dk · Joined: Feb 12, 2019 Posts: 115 Location: Europe

Way cool! I have a waveshaper panel on hold, since I didn't know what to fill it up with yet... definitely going to try this!

Grumble · Posted: Thu Oct 08, 2020 10:52 am Post subject: