Author Topic: Can a distortion pedal produces square waves?  (Read 1154 times)

ThinkingMan

Can a distortion pedal produces square waves?
« on: December 02, 2019, 08:37:34 AM »
Can a distortion pedal (not fuzz pedals) produces square waves on the oscilloscope such as those that were produced by fuzz pedals but without 100% sounding like fuzz pedals? If there are such distortion pedals out there, what are the names of those distortion pedals?
« Last Edit: December 02, 2019, 08:39:33 AM by ThinkingMan »

Ben N

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Re: Can a distortion pedal produces square waves?
« Reply #1 on: December 02, 2019, 08:50:28 AM »
No matter you call it, anything that looks like a square wave will also sound like a square wave. Or am I missing your meaning?

Mark Hammer

Re: Can a distortion pedal produces square waves?
« Reply #2 on: December 02, 2019, 09:20:25 AM »
The short answer is "No".  Why?  Because applying high gain to a signal not only forces the fundamental to run out of headroom (which would lead us to expect "squaring"), but also applies the same amount of gain to whatever harmonics/partials accompany that fundamental.  Those harmonics do not have the same amplitude as the fundamental, so amplifying them by 100x or 200x or even 500x still leaves them below the clipping threshold.  The result is that they are added to the fundamental, rather than displaced by it.

Stated bluntly, you're never going to get something out of a guitar string pushed to the limits that will sound like the square-wave output from an oscillator of the very same note.  That doesn't mean it's "bad", just not identical.  You will, however, get closer to an oscillator tone if the guitar is seriously filtered before applying gain, such that all those "contaminating" harmonics are removed.  But, as you can imagine identifying the right filtering for every single note on every single string is not exactly stick-it-in-a-1590B stuff.

duck_arse

Re: Can a distortion pedal produces square waves?
« Reply #3 on: December 02, 2019, 09:35:03 AM »
if a distortion pedal does produce squarewaves [on the oscilloscope], how does it then differ from a fuzz that produces squarewaves [on the oscilloscope]? are they different squarewaves?

also - popcorn. in a square container, natch.
"Don't roll those bloodshot eyes at me."

ThinkingMan

Re: Can a distortion pedal produces square waves?
« Reply #4 on: December 02, 2019, 09:39:26 AM »
So, the only "distortion" pedals that produced square waves on the oscilloscope are fuzz pedals?

I have just found this. ProCo Rat is a distortion pedal but when you turn up the treble you'll get almost "perfect" square waves on the oscilloscope. Just see at the near end of this link https://www.electrosmash.com/proco-rat and picture below



This is another one showing the waveforms produced by a ProCo Rat https://www.facebook.com/mceaudio/photos/for-nerdsproco-rat-output-waveform-with-controls-all-at-10basicallyyou-can-use-i/1536182406489308/



I listened to the sounds of ProCo Rat on Youtube, it does sounds a little bit fuzzy but not as chaotic as most fuzz pedals. Some fuzz pedals sound smooth too especially Lovepedal Silicon Fuzzmaster.

Ben N

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Re: Can a distortion pedal produces square waves?
« Reply #5 on: December 02, 2019, 09:49:00 AM »
Those waveforms are what you get when you feed a nice clean single-frequency signal into a Rat, and it more or less squares it up. I think Mark's point above is that actual real-life guitar inputs don't work that way, because they include harmonics and dynamics, not to mention multiple fundamentals.
« Last Edit: December 02, 2019, 01:46:01 PM by Ben N »

amz-fx

Re: Can a distortion pedal produces square waves?
« Reply #6 on: December 02, 2019, 10:09:31 AM »
The main reason that distortion pedals will not have a pure square wave sound is that they almost always have capacitors in the design that roll off the high end of the signal to reduce noise, and because it is more pleasing most of the time to cut extreme highs. This leads to the wave not having the sharp, square look.

Also, fuzz pedals do not usually have a 50:50 duty cycle as found in a square wave. It is common for a fuzz wave to be more rectangular than square; meaning that the duty cycle is skewed away from each wave half being identical to the other.

Diodes are not sharp clippers; there is a log response to the diode conduction that tends to round off the waves. With enough gain going into the diodes this can be minimized but it is never going to have really sharp corners. An op amp comparator will give more square-like waves, and was the basis for several of the Craig Anderton fuzz circuits.

regards, Jack

PRR


teemuk

Re: Can a distortion pedal produces square waves?
« Reply #8 on: December 03, 2019, 09:38:52 AM »
Fuzz effect also sounds like 'fuzz' primarily due to specific pre-distortion frequency emphasis, not because its output is square wave. In fact, most fuzz effects do not produce such.

antonis

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Ben N

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Re: Can a distortion pedal produces square waves?
« Reply #10 on: December 04, 2019, 07:24:50 AM »
Walters? Is that you?  :o