The Corruptor - CMOS Ring Modulator

[Freppo]

A few days ago I started breadboarding an idea I had for a ring modulator.
This is the result and i'm very happy with it. Sounds great (for a ringmod lol).


(the schematic is missing stuff like power connections, dc-filtering, decoupling..)

I got the idea from the KORG MS20 synth which uses a CD4011 to produce psuedo ringmod sounds.

I have built it on vero and I will verify a PCB layout tomorrow. Soundclips coming soon.
I guess ringmods are not the most popular kind of effect, but I hope someone finds this interesing

cheers
/ Freppo

[Hatredman]

Don't know if I'm speaking nonsense, but isn't a ring modulator something that modulates two external signals?

[Freppo]

Don't know if I'm speaking nonsense, but isn't a ring modulator something that modulates two external signals?

Yes, that's true. The first input usually gets modulated against some kind of tone generator.
This one has a oscillator built in, as with most ringmods for guitar that I have seen.

[commathe]

Interesting! I've used the 4070 for ringmod square sounds before. I don't get how the square/tri switch works though? The 4070 is a digital logic chip. It'd only maybe shorten the pulse width of the modulator (it'd spend less time above the logic threshold). It wouldn't actually make a triangle output after the 4070.

Your freaky way of generating another wave from an input is cool though! Definitely going to be trying that out! Is it some sort of envelope generator?

[nocentelli]

I happen to have a 4069 and a 4070 on the breadboard right now (just tried the Silver Fox octaver) and will try this tonight. Two questions: Does it have the usual ring mod carrier bleed? And do you ever sleep?

[deadastronaut]

And do you ever sleep?

i think he's rechargable...

cool stuff freppo..(though ring mods aren't my thing..)

[Freppo]

I don't get how the square/tri switch works though? The 4070 is a digital logic chip. It'd only maybe shorten the pulse width of the modulator (it'd spend less time above the logic threshold). It wouldn't actually make a triangle output after the 4070.

Yes, you are right about that. When feeding the 4070 a triangle wave, what comes out is only a shorter width pulse
It sounds warmer and more bell like then the 50/50 square though, just as expected from a triangle in a analog ringmod
But I guess I should call the switch something else than square/triangle. Maybe short/long? I dunno...

Another gate on the cd4070 could be used for full modulation of the pulse width of the carrier signal
It was something I had on the breadboard for a while, and it works great but it felt alittle overkill.
I will post a schematic later on how to do that if someone want to add that feature.

Your freaky way of generating another wave from an input is cool though! Definitely going to be trying that out! Is it some sort of envelope generator?

The signal gets recitified and then triggers a gated RC oscillator, which means that the oscillator is only running while playing.
So no carrier bleedthough, as you will see and hear in the video below.

do you ever sleep?

lol. Not really. I'm spending way too much time on this hobby.  

Anyway, here is a video. Sorry about the sound-quality.. just a quick ipad video.

It starts to sound like a regular ringmod at about 3:30 when I have turned up the frequency
I find that most ringmods are almost totally unusable at low frequencies, but not this one

/ Freppo

[anotherjim]

Yet again, another interesting FX from you Freppo. Neat idea to gate the local oscillator from a simple envelope detector.

Hmmm, 3 XOR's doing nothing. That can't stand!
Let's see... a second path, Frequency doubler on the Schmitt output and another on the oscillator output and both doublers to the last XOR, blend pot between ring mods to the output. Result, 2 ring modulated signals an octave apart?
Cost = 2 R's, 2 C's and one pot.

[bluesdevil]

Damn, another cool easy to build project! I would add a clean blend control on mine.
Thanks again Freppo for sharing!

[digi2t]

Yet again, another interesting FX from you Freppo. Neat idea to gate the local oscillator from a simple envelope detector.

Hmmm, 3 XOR's doing nothing. That can't stand!
Let's see... a second path, Frequency doubler on the Schmitt output and another on the oscillator output and both doublers to the last XOR, blend pot between ring mods to the output. Result, 2 ring modulated signals an octave apart?
Cost = 2 R's, 2 C's and one pot.

Could you draw that out for this noob, please?

Sounds amazing!!!

[cloudscapes]

triangle oscillator into cmos gate? don't these things only deal in logic highs and lows?

[Freppo]

Result, 2 ring modulated signals an octave apart? Cost = 2 R's, 2 C's and one pot.

Yes, free unused XOR gates bugs me too. 
I had tried to add an octave up, but only on the squared signal or on the modulated output, which didn't result in anything useful..
Never thought of doing it that way you are thinking, I might have to give it a try
It might be overkill, that is so much octaveyness (is that a word?) happening already.

Another approach would be to use something else to square up the signal to free up half the cd4069 for dual carrier oscillators..
Something similar to the Caralinbread Heliotrope? Could be worth trying, for another pedal. That would still leave the remaining XOR's unused though

Damn, another cool easy to build project! I would add a clean blend control on mine.

I havem't thought of doing a blend control.. maybe I'll play around with that.
It would probably not work very good with the clean signal.. but maybe with the square'd signal.

triangle oscillator into cmos gate? don't these things only deal in logic highs and lows?

That's right, and I have already answered to that question.

When feeding the 4070 a triangle wave, what comes out is only a shorter width pulse
It sounds warmer and more bell like than the 50/50 square, similar to a triangle in a analog ringmod
But I guess I should call the switch something else than square/triangle. Maybe short/long? I dunno...

Glad so many people are showing interest

[anotherjim]

If I may, here's a quick MS paint desecration of Freppo's work

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Cloudscape, they are indeed binary devices, but slewing the edges of a square wave into a triangle will vary the width of the square wave seen by the chips inputs. That will change the timbre.

I haven't fed the doubler in the mod I've drawn from the triangle switch because the doubler circuit works best with a really fast rise and fall time.

[anotherjim]

Ooops,
I don't know what's going on, but I can neither get a preview of a post or get an embedded image to show?
Try again...

[Freppo]

Here is a verified vero layout just as my schematic/demo

Full size: http://parasitstudio.weebly.com/uploads/2/4/4/9/2449159/corruptor.png

I will be super busy for a couple of days now, so this is probably the last thing I will post in a while.
Hopefully I will have some time to return to this project again soon!

edit: nice one anotherjim! I will have to try that on the breadboard

cheers
/ Fredrik

[digi2t]

Thank you very much for the visual. I guess the germanium BMP breadboard project is going to take a back seat for now. 

[Freppo]

Forum is back

Thank you very much for the visual. I guess the germanium BMP breadboard project is going to take a back seat for now.  

I'm glad you like it!


I have played around with the ringmod on the breadboard today.. so much for working and doing other things in life  

I tried the octave up idea from anotherjim. It kinda works as expected: it lets you sweep between two modulated signals one octave apart.
However, they don't blend well - it just sounds like a regular ringmod only a bit dirtier. You can distinguish the octaves with the signals mixed.  

I also tried running two oscillators for the carrier signal. It just sounded messy and unusable..

I guess I'll stick with my original version. I might even ditch the switch to keep it even simpler.
..or I might replace the switch with a knob that lets you control the pulse width completely, like this:



So, those are my experiments today for "The Corruptor".

However, I did try something else based on this one: a ring modulator running a sequencer for the carrier signal.  
I'll share more about that later.. I have to draw up the schematic.
It sounds very cool. But a step away from guitar stuff into more synthy territory

l Need to get some sleep now..
/ Freppo

[commathe]

Your freaky way of generating another wave from an input is cool though! Definitely going to be trying that out! Is it some sort of envelope generator?

The signal gets recitified and then triggers a gated RC oscillator, which means that the oscillator is only running while playing.
So no carrier bleedthough, as you will see and hear in the video below.

I see it now! Reminds me a little of the Weird Sound Generator by Music From Outer Space. Definitely going to have to keep this little trick in mind!

[StephenGiles]

EH used a 4070 on their rack guitar synth for a ring modulator!

[anotherjim]

Ah well, thanks for trying it Freppo. I should have known - it's never as good as you think it might be to mix sounds that are perfectly synchronous - no matter how differently they are processed.