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DIY Stompboxes => Building your own stompbox => Topic started by: Freppo on November 17, 2014, 07:00:22 PM

Title: The Corruptor - CMOS Ring Modulator
Post by: Freppo on November 17, 2014, 07:00:22 PM
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).

(http://parasitstudio.weebly.com/uploads/2/4/4/9/2449159/2605348_orig.png)
(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
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Hatredman on November 17, 2014, 07:22:47 PM
Don't know if I'm speaking nonsense, but isn't a ring modulator something that modulates two external signals?
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on November 17, 2014, 08:34:27 PM
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.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: commathe on November 17, 2014, 09:22:18 PM
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?
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: nocentelli on November 18, 2014, 12:32:45 AM
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?
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: deadastronaut on November 18, 2014, 04:02:16 AM
And do you ever sleep?



i think he's rechargable... ;D

cool stuff freppo..(though ring mods aren't my thing..)
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on November 18, 2014, 06:46:14 AM
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. :icon_rolleyes:  :icon_lol:

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
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: anotherjim on November 18, 2014, 07:39:18 AM
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.

Title: Re: The Corruptor - CMOS Ring Modulator
Post by: bluesdevil on November 18, 2014, 03:32:17 PM
Damn, another cool easy to build project! I would add a clean blend control on mine.
Thanks again Freppo for sharing!
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: digi2t on November 18, 2014, 04:39:51 PM
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!!!
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: cloudscapes on November 18, 2014, 05:28:03 PM
triangle oscillator into cmos gate? don't these things only deal in logic highs and lows?
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on November 18, 2014, 05:56:17 PM
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.  :icon_lol:
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 :P

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 :)
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: anotherjim on November 18, 2014, 05:57:33 PM
If I may, here's a quick MS paint desecration of Freppo's work ;)

(http://[URL=http://s1374.photobucket.com/user/ashdalestudio/media/Frepposringmodoctavemod_zpsa0879079.png.html][IMG]http://i1374.photobucket.com/albums/ag414/ashdalestudio/Frepposringmodoctavemod_zpsa0879079.png)[/URL][/img]

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.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: anotherjim on November 18, 2014, 06:00:41 PM
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...
(http://i1374.photobucket.com/albums/ag414/ashdalestudio/Frepposringmodoctavemod_zpsa0879079.png)
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on November 18, 2014, 06:02:58 PM
Here is a verified vero layout just as my schematic/demo
(http://parasitstudio.weebly.com/uploads/2/4/4/9/2449159/7282138_orig.png)
Full size: http://parasitstudio.weebly.com/uploads/2/4/4/9/2449159/corruptor.png (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
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: digi2t on November 18, 2014, 07:21:37 PM
Thank you very much for the visual. I guess the germanium BMP breadboard project is going to take a back seat for now.  :icon_mrgreen:
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on November 19, 2014, 06:54:33 PM
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.  :icon_mrgreen:
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  :icon_rolleyes:

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.  :icon_sad:

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:

(http://parasitstudio.weebly.com/uploads/2/4/4/9/2449159/6710321_orig.png)

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.  :icon_mrgreen:
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
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: commathe on November 19, 2014, 09:02:27 PM
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!
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: StephenGiles on November 20, 2014, 02:58:08 AM
EH used a 4070 on their rack guitar synth for a ring modulator!
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: anotherjim on November 20, 2014, 06:44:17 AM
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.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on November 21, 2014, 07:04:40 AM
EH used a 4070 on their rack guitar synth for a ring modulator!
Cool, I didn't know that. :)

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.
Yes, too bad because I really liked the idea.

Here is something else I've been playing around with. A envelope controlled ring mod sequencer:  :icon_mrgreen:


I found some usable setting at about 4:20, so you can skip ahead  :icon_lol:
The schematic has 4 pots, 3 rotary switches and 5 toggle switches... But I doubt I'll ever finish this one..
It's just too wierd even for me... or what do you guys think?

(http://parasitstudio.weebly.com/uploads/2/4/4/9/2449159/9773386_orig.png)

cheers
/ Freppo
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: anotherjim on November 21, 2014, 07:40:18 AM
I'm lost for words for now!

Can you write a bit of a description please Freppo?

I kind of get there's an 8 channel mux driven by the counter that's clocked by an LFO. The Modulator oscillator built around the mux looks a bit novel.

You've lost the schmitt trigger after the pre-amp. Is it not really needed? You can make the 4070 XOR that's replaced the 2xinverter one into a schmitt with the usual 2 resistors since it's non-inverting.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on November 21, 2014, 08:18:12 AM
Hehe I'll take that as a compliment. :)

It might be hard to see, but the carrier oscillator (the top one) and the LFO are basically the same.
Think of the CD4051 as a pot replacement. Insted we have a resistor-latter that sets the frequency.

This idea comes from this synth sequencer
http://www.milkcrate.com.au/_other/sea-moss/04_seq.gif (http://www.milkcrate.com.au/_other/sea-moss/04_seq.gif)
It might be easier to see how the resistor latter replaces the usual feedback resistor with a simple 40106 oscillator.
I just adapted the idea to the 4069 RC oscillator. Wish I could explain it better...

Yes, the schmitt trigger would be a big improvement.. Now it's way too gated.
But i'm not sure how to set up a schmitt trigger with the 4070. Is this correct?
(http://parasitstudio.weebly.com/uploads/2/4/4/9/2449159/6397442_orig.png)

I have to run to work now..


cheers / Freppo
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: peterg on November 21, 2014, 09:52:14 AM
Freppo - I'm going straight to PCB with this. Is this schematic confirmed?

(http://parasitstudio.weebly.com/uploads/2/4/4/9/2449159/6710321_orig.png)

Title: Re: The Corruptor - CMOS Ring Modulator
Post by: anotherjim on November 21, 2014, 10:42:33 AM
Got it now -  the 2 inverters around the "fine tune" are a standard CMOS r-c osc. Didn't look like one to me on first reading. Thanks.

You don't need 2 gates to make the Schmitt , 1 will do if it's not inverting (need positive feedback). As you had the unused input tied low, the gate is Non-inverting so it's just the feedback resistor and one input resistor to add, just as you had with the original 2 inverter design (using 2 just made it non-inverting)  but with only 1 gate.
BTW, if you tie all inputs of an XOR together, you make a special kind of logic - The "Exclusive Always, Inclusive Never" gate - No input will ever get through it
 ;D
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on November 21, 2014, 11:49:20 AM
Freppo - I'm going straight to PCB with this. Is this schematic confirmed?
Cool! Both schematics I posted are verified.
I recommend using the first schematic I posten and omit the switch (100n cap directly to ground)
I didn't find the pulse width control to be very useful...
(http://parasitstudio.weebly.com/uploads/2/4/4/9/2449159/2605348_orig.png)
(the schematic is missing stuff like power connections, dc-filtering, decoupling..)

I have a PCB layout done aswell, but I want to verify it myself before sharing it.
Hopefully I'll be able to do that in a couple of days.

You don't need 2 gates to make the Schmitt , 1 will do if it's not inverting (need positive feedback).
Ahh, of course. Thanks!

BTW, if you tie all inputs of an XOR together, you make a special kind of logic - The "Exclusive Always, Inclusive Never" gate - No input will ever get through it ;D
;D  :icon_lol:
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: peterg on November 21, 2014, 12:08:03 PM
Thanks Freppo
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: digi2t on November 21, 2014, 04:02:08 PM
Quote
I found some usable setting at about 4:20, so you can skip ahead

Jeez Louise... you had me at "PLAY". Blowin' my mind man! I'm going to vero with this. Are there any special power considerations? Biploar, or straight up 9v?
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: glops on November 22, 2014, 12:45:02 AM
Man, great stuff. Great site with low parts count projects that have massive sounds that are in the realm of what I dig.

I've built a few Craig Anderton ring mods and a Ring Stinger. Also bought a boutique one for a good price awhile back. I love ring mods, gonna definitely try this baby out.

What I really liked about the craig anderton one was the addition of an effects loop. One of my favorite sounds was the CA ring mod with a fuzz with delay in the loop.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on November 22, 2014, 08:48:57 AM
Jeez Louise... you had me at "PLAY". Blowin' my mind man! I'm going to vero with this. Are there any special power considerations? Biploar, or straight up 9v?
I'm glad you like it  :icon_biggrin: Just straight up 9v single supply. I would love to see a vero layout!
Just check the datasheets for power connections. It's +9v to either pin 14 or 16 and ground to either 7 or 8  depending on the size of the chip.

I made a few tiny changes to the schematic. A schmitt trigger as anotherjim suggested is one of them (thanks!).
It helps a bit with the sustain. It works ok now with hot humbuckers using neck pickup.
But with lower output pickups it would be a good idea to use a booster, compressor or distortion at the front.
(http://parasitstudio.weebly.com/uploads/2/4/4/9/2449159/6314022_orig.png)

Man, great stuff. Great site with low parts count projects that have massive sounds that are in the realm of what I dig.
Thanks! I gonna check out that anderton ringmod. Is it the one with the obsolete chip?
An effects loop would not really be possible to add with this one though, since it works with squared up signals

cheers / Freppo
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: digi2t on November 22, 2014, 04:44:00 PM
How about adding this to the front end?

(http://www.jer00n.nl/pics/opampbooster.png)
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: anotherjim on November 22, 2014, 04:48:06 PM
Well, you could replace the inverter working as the envelope detector with an XOR. Unused input tied high makes it an inverter (versatile chip isn't it?). That would free an inverter to give a second preamp stage.

Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on November 22, 2014, 05:39:10 PM
Well, you could replace the inverter working as the envelope detector with an XOR. Unused input tied high makes it an inverter (versatile chip isn't it?). That would free an inverter to give a second preamp stage.
That's great! I didn't know that. I'm still learning this stuff. Thanks! You brought alot of great ideas to this thread. :)
Like this? I will try it out on the breadboard tomorrow.
(http://parasitstudio.weebly.com/uploads/2/4/4/9/2449159/6630586_orig.png)

How about adding this to the front end?
Hopefully a booster at the frontend won't be needed now  :icon_smile:

/ Freppo
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: digi2t on November 22, 2014, 06:21:06 PM
Awaiting your test results before I commit to vero. :icon_cool:
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on November 23, 2014, 03:43:39 PM
Awaiting your test results before I commit to vero. :icon_cool:

Testing done! The sustain is good now with two preamplifier stages.
I made a few minor changes and also added a gate on/off switch that I felt was worth adding.
Now with the gate off we can use this circuit as a regular sequencer synth aswell :)

(http://parasitstudio.weebly.com/uploads/2/4/4/9/2449159/3879638_orig.png)
Full size version: http://parasitstudio.weebly.com/uploads/2/4/4/9/2449159/ringmod-sequencer_final.png (http://parasitstudio.weebly.com/uploads/2/4/4/9/2449159/ringmod-sequencer_final.png)

It can also do regular square-wave fuzz (with the blend turned to the "clean" sound) and the sequencer turned off
With the blend turned the other way we get all the standard ringmod sounds as my first ringmod version.  :icon_biggrin:

I'm going away on tour for a week, so I won't have time to tinker with it. But I think this is pretty much the final version. :)

cheers / Freppo
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: anotherjim on November 23, 2014, 04:18:50 PM
COOL  ;D
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Jamforthelamb on November 29, 2014, 01:25:31 AM
:crosses fingers for vero layout of this one:
Seriously man, sounds awesome!
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: peterg on December 19, 2014, 03:19:29 PM
Freppo et al. I have the original version of breadbaord. There is oscillation when the strings are muted. Is there anything in particular I shouuld look for the stop this from happening?
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on December 20, 2014, 06:46:32 AM
Freppo et al. I have the original version of breadbaord. There is oscillation when the strings are muted. Is there anything in particular I shouuld look for the stop this from happening?

Does it help to adjust the 100K trimpot?
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: peterg on December 20, 2014, 09:00:45 AM
It adjusts the oscilllation but doesn't make it go away. I'l try some other 4069s.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: anotherjim on December 20, 2014, 02:09:09 PM
At minimum resistance, that gate/release trimmer should definitely stop the oscillator (it will then be forcing the inverter input to ground, whatever the signal does, then it's holding the oscillator input high via the diode, bypassing the timing). Have you got a diode the wrong way around?
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: peterg on December 20, 2014, 04:25:50 PM
Diodes are good. The oscillation starts at the straight joined inverters and continues throughtout the circuit
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: digi2t on December 21, 2014, 04:58:59 PM
Should the unused quad on the 4070 be tied high (or low)?
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on December 22, 2014, 05:44:18 AM
Should the unused quad on the 4070 be tied high (or low)?
The unused inputs on the CD4070 can be tied either both high or both low. It doesn't matter. :)
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: digi2t on December 24, 2014, 07:33:35 PM
Well, here's my initial layout for the "all bells and whistles" version. I've gone over it one time, and I think it's OK, but another set of eyes would be welcome. I'll go over it again over the next few days. Let me know if you see something amiss.

(http://i214.photobucket.com/albums/cc196/digi2t/Corruptor/Corruptorringmod_vero_zps2d71f853.jpg) (http://s214.photobucket.com/user/digi2t/media/Corruptor/Corruptorringmod_vero_zps2d71f853.jpg.html)
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on December 25, 2014, 12:02:26 PM
Well, here's my initial layout for the "all bells and whistles" version. I've gone over it one time, and I think it's OK, but another set of eyes would be welcome. I'll go over it again over the next few days. Let me know if you see something amiss.

Sweet! That's great. :) I'll have a look later this weekend after I get back home from x-mas.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: digi2t on December 26, 2014, 09:57:19 AM
Did a second pass, one cut under IC4 in the wrong place (for +9 jumper to pin 16). Should be one hole to the left. Other than that, everything seems to follow the schematic.

I'll update it tonight, and include the BOM.

Crap... I really want to build this now, but I've got too much on my bench at the moment. I have to make some room. :icon_rolleyes:
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: digi2t on December 26, 2014, 09:12:10 PM
Corrected and updated.

(http://i214.photobucket.com/albums/cc196/digi2t/Corruptor/Corruptorringmod_vero_zps8703cf1f.jpg) (http://s214.photobucket.com/user/digi2t/media/Corruptor/Corruptorringmod_vero_zps8703cf1f.jpg.html)
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: peterg on December 31, 2014, 11:39:41 AM
Need some debug help please. I am working on the original circuit. There were problems with oscillation when I breadbboarded the circuit. I resolved that by swapping 4069 chips. Now that I have completed a PCB I have the problem again. There is a hum generated by the chip to the input signal when I test with the multimetre although there is no voltage present. Below is the schematc with the voltages clouded. Any suggestions?
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=51843&g2_serialNumber=1)
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: anotherjim on January 01, 2015, 11:19:57 AM
Need some debug help please. I am working on the original circuit. There were problems with oscillation when I breadbboarded the circuit. I resolved that by swapping 4069 chips. Now that I have completed a PCB I have the problem again. There is a hum generated by the chip to the input signal when I test with the multimetre although there is no voltage present. Below is the schematc with the voltages clouded. Any suggestions?
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=51843&g2_serialNumber=1)

Are you using all the same components in the board that you used on the breadboard?
Just wondering if you have a faulty component other than a 4069.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on January 01, 2015, 04:13:02 PM
Need some debug help please. I am working on the original circuit. There were problems with oscillation when I breadbboarded the circuit. I resolved that by swapping 4069 chips. Now that I have completed a PCB I have the problem again. There is a hum generated by the chip to the input signal when I test with the multimetre although there is no voltage present. Below is the schematc with the voltages clouded. Any suggestions?
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=51843&g2_serialNumber=1)

Sorry about the late reply.. I'm too busy too do any DIY stuff for the moment as I am moving my studio to the new house for a recording starting tomorrow
I can't see your picture of the schematic. Can you upload it again? I have built the original version on breadboard, vero and PCB without any issue.  :icon_confused:
/ Freppo

Title: Re: The Corruptor - CMOS Ring Modulator
Post by: peterg on January 02, 2015, 12:02:14 AM
Jim. I checked the components. They seem to be intact.
Freppo. Hopefully you can see the attached documents. They are yyour original schematic with my voltage readings and the pcb layout I created. It is my first attempt at using all board mount  componts
 https://db.tt/8fwQTod7 (https://db.tt/8fwQTod7)
https://db.tt/c39i8Lba (https://db.tt/c39i8Lba)
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: anotherjim on January 02, 2015, 04:37:35 AM
Voltages suggest circuit "should" be silent.
If you hook up a probe wire connected to ground, use it to "ground out" any signal at 4069 pins  8 then 4. If the noise stops with either one it should help determine the source.

I have a suspicion it could be the schmitt trigger (4069 pins 11 to 8) jittering because it's input voltage is "half way". It shouldn't jitter. Maybe R3 needs increasing - try 33-47k.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: peterg on January 02, 2015, 10:36:59 AM
Jim. Thanks for the probe/ground suggestion. I think you noticed on the marked up schematic that the circuit starts at pin 13 down to 8 and then from 1 to 6. Grounding 13 to 8 and 1 kills the noise. Grounding 2 to 6 slightly quiets it. I haven't changed R3 yet but will give it a go.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: peterg on January 04, 2015, 09:03:52 PM
Thanks Jim. 47k worked.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on January 05, 2015, 08:53:58 AM
Thanks Jim. 47k worked.

I'm glad you got it sorted! That's an awesome looking pedal, and the PCB layout looks great aswell.
Nice job! :) I have yet to finish my build.. Too much work at the moment.

/ Freppo
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: peterg on January 05, 2015, 11:34:04 AM
Thanks Freppo.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: digi2t on January 06, 2015, 06:08:13 PM
Voltages suggest circuit "should" be silent.
If you hook up a probe wire connected to ground, use it to "ground out" any signal at 4069 pins  8 then 4. If the noise stops with either one it should help determine the source.

I have a suspicion it could be the schmitt trigger (4069 pins 11 to 8) jittering because it's input voltage is "half way". It shouldn't jitter. Maybe R3 needs increasing - try 33-47k.


Which one is R3?  ???
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: peterg on January 06, 2015, 06:25:31 PM
It's the 10k between the first and second inverters
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: digi2t on January 06, 2015, 10:20:59 PM
It's the 10k between the first and second inverters

Wait... which version are you talking about? On the "full version" I see a 10K after the second inverter.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: anotherjim on January 07, 2015, 07:30:02 AM
This one
https://db.tt/c39i8Lba

The smaller the input R to a Schmitt trigger is compared to the feedback R, the more it acts like a zero crossing detector. The input from the first inverter is biased at the same voltage as the signal zero crossing. Any noise from the input can be interpreted as a signal if the Schmitt is too sensitive.
To suppress input  noise, you need the upper and lower thresholds of the Schmitt trigger to be at significantly different voltages above and below the signal zero crossing level. Too different, and it will be too insensitive and signal will drop out too soon in the note decay. So, it has to be some compromise. I suppose the 10k input R should ideally have a 50k trimmer resistor in series with it if you wanted to find the best value.

I'd also suggest that care is taken to keep the input signal path clean - screened cable all the way from input to stomp switch to jack.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: digi2t on January 07, 2015, 10:55:36 AM
Ahhhhh, OK. Now I see. Another question...

In this diagram;

(http://parasitstudio.weebly.com/uploads/2/4/4/9/2449159/3879638_orig.png)

would the 10K after the second inverter have to be adjusted as well? This is the diagram that I used for the vero layout, but I've yet to play with it.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: anotherjim on January 07, 2015, 11:35:43 AM
Maybe. On the face of it, the later version is more likely to get noise into the Schmitt due to more gain from 2 pre-amps. But it depends. I don't think Freppo has an issue with it.
At least we know a fix if it does happen.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on January 17, 2015, 06:40:30 AM
Hi folks
Here's a small update on my progress with this project

I have built the simple version on both vero and my own PCB layout, both verified. :)
As soon as I have boxed it I will put up the layouts and a demo video on my blog.

I did get sputtering on my PCB layout just as peterg did, so I changed R3 to 47K which helped.
It may be needed to change that on the sequencer version aswell... We'll see.

I have been trying to verify a PCB layout for the sequencer version, "the King Corruptor".
But both times I have built it up I get the same problem, the oscillator isn't working at all.
The LFO, envelope follower and the 4040 works fine though... I can't find any fault on my PCB layout.
Maybe someone else can have a look and see if I missed something?
Here's my PCB layout: http://parasitstudio.weebly.com/uploads/2/4/4/9/2449159/king_corruptor.pdf (http://parasitstudio.weebly.com/uploads/2/4/4/9/2449159/king_corruptor.pdf)
I will put it up on the breadboard again just too verify the schematic... maybe it's not correct  :icon_neutral:

cheers / Fredrik
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on January 23, 2015, 04:10:30 PM
I finally finished the barebones version of this ringmod.


vero and PCB layout can be found in my blog:
www.parasitstudio.se (http://www.parasitstudio.se)

I got the enclosure for the sequencer version prepared. Will finish boxin it in a few days. :)
/ Freppo
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: blackieNYC on January 23, 2015, 05:04:19 PM
Stopped about 15 seconds into the demo.
Your schematic on page 2, with the 47k change and the cap to ground with no switch,right?
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on January 23, 2015, 05:30:19 PM
Stopped about 15 seconds into the demo.
Your schematic on page 2, with the 47k change and the cap to ground with no switch,right?
Yes, that's correct. :) The schematic I ended up with is included in the PCB layout PDF on my blog.

I should mention that i'm happy I had so much great input from anotherjim and from peterg that reported on his build.
Thanks guys!
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: digi2t on January 26, 2015, 11:44:13 PM
Following some corrections on the "King Corruptor" schematic that Frep sent me, I've updated the vero.

(http://i214.photobucket.com/albums/cc196/digi2t/Corruptor/Corruptor%20ringmod_vero_zpsq8tgkifu.jpg) (http://s214.photobucket.com/user/digi2t/media/Corruptor/Corruptor%20ringmod_vero_zpsq8tgkifu.jpg.html)

No drastic changes, just some off-board wiring shuffling. I also changed the 10K resistor on the input side to a 100K trimmer (VR 2). Just dial it to get rid of the oscillation, or, insert the 47K resistor here.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on January 27, 2015, 06:20:21 AM
Thanks Dino! Great work on the layout. It should be good now :)

I finally boxed it up. Here's a demo.


 :icon_mrgreen:

Maybe it deserves a new thread, so it's not confused with the original simple version?
cheers / Freppo
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: digi2t on January 27, 2015, 06:45:34 AM
All I can say is.....

 :icon_eek:

2:07 to 2:13 sounds like doom. Reminds me of Escobedo's DOF, making out with an Uglyface. Everything else is pure insanity.

Daddy likes!
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: digi2t on February 06, 2015, 10:18:38 PM
It's done! All I can say... it's completely off the hook brothers and sisters. Here are the pics. Not my cleanest build, it's a bit of a spag monster, but it works fine.

(http://i214.photobucket.com/albums/cc196/digi2t/Corruptor/DSCF4352_zpsia5j4ygk.jpg) (http://s214.photobucket.com/user/digi2t/media/Corruptor/DSCF4352_zpsia5j4ygk.jpg.html)

(http://i214.photobucket.com/albums/cc196/digi2t/Corruptor/DSCF4350_zps4r8wvxqw.jpg) (http://s214.photobucket.com/user/digi2t/media/Corruptor/DSCF4350_zps4r8wvxqw.jpg.html)

I've updated the vero. Some minor corrections, and I also added a rate LED. You can run it directly off the rate pot, negative leg to the pot, and positive to ground. No resistor necessary. It only flashes when there's a signal output, which is kind of cool.

(http://i214.photobucket.com/albums/cc196/digi2t/Corruptor/Corruptor%20ringmod_vero_zpstyd7hvdd.jpg) (http://s214.photobucket.com/user/digi2t/media/Corruptor/Corruptor%20ringmod_vero_zpstyd7hvdd.jpg.html)

I'll do a video soon.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on February 07, 2015, 06:57:12 PM
Awesome!! So many LED's  ;D Me like.
I think it looks really neat and tidy inside.

Which function is the second stompswitch? (sequencer on/off I guess?)

Looking forward to the video... :)
cheers
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: digi2t on February 07, 2015, 11:16:15 PM
Awesome!! So many LED's  ;D Me like.
I think it looks really neat and tidy inside.

Which function is the second stompswitch? (sequencer on/off I guess?)

Looking forward to the video... :)
cheers

Second switch is as you called it, sequencer on/off. I preferred to have it as a footswitch, rather than a toggle. Not totally crazy about the wiring, but I must admit, cleaner than the Infinitphase.  :D
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: digi2t on February 09, 2015, 08:23:16 PM
Slight correction on the vero (wire switch on the fine tune pot). Here is the final product,

(http://i214.photobucket.com/albums/cc196/digi2t/Corruptor/Corruptor%20ringmod_vero_zpsbo6gbip5.jpg) (http://s214.photobucket.com/user/digi2t/media/Corruptor/Corruptor%20ringmod_vero_zpsbo6gbip5.jpg.html)
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: blackieNYC on March 04, 2015, 08:31:08 PM
Hi all
I've got a corruptor on the breadboard. Freppo has been most helpful - thank you. I'm using a 4049 instead of a 4069 which works if you address the change of pinout.  The oscillator and the guitar signal show up at the 1 and 2 inputs of the 4070 at a healthy 9v square wave, but the output at the pin 3 output is incredibly low but present.  10mv or so.  If I crank the amp, and put a cap straight to pin3 I can hear it and it works fine, just very low.
I discovered something - the 4049 is a 4049UBE.  Unbuffered.  I have one of these in a 49er distortion pedal, works fine.  Does the input of the 4070 not like the unbuffered output? I thought cmos played nice with cmos.  Additionally, when you look at the datasheets, you see what looks like the same output circuit on the equivalent circuit diagram.  Is there something I can insert as a workaround.  Don't have any buffered 4049s around. Nor 4069.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: duck_arse on March 05, 2015, 10:14:57 AM
the 4069 is an unbuffered part, it comes no other way afaik but ibwb. the 4049ube should work the same.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: blackieNYC on March 05, 2015, 10:03:46 PM
Figured out my (basic) corruptor problem.  4049s work just fine (again, mind the different pinout).  I tried 2 4070s, still didn't work.  I changed the wiring to use a different gate on the 4070, and it lives!  I either had two 4070s with one dead XOR in the same position no.1, or...  I have a bad spot in this extremely old breadboard, which has probably had even older resistors stuffed in it, with big fat 14 ga. legs.
Now it's great!
But, of course, there was a little sumthin' about the malfunctioning performance that I'm trying to recreate slightly....    Just can't finish a pedal!
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: blackieNYC on March 09, 2015, 11:24:02 PM
Awesome with a blend control! Somewhere around a 50/50 mix of the ringmod output at the output of the 4070 and the straight fuzz from the pin 1input to the 4070.   No additional 4070 gates seem neccesary.  Add a 100k branching off from pin 1, put that at one end of a 100kb pot.  The other end of the pot ties in just after the 100kb you see on the output of the 4070.  Use the wiper out as another Jim suggested on his add-on. 
I have found I like the 50/50 balance point so much I'm getting rid of the pot for a fixed resistor on a switch - 1for regular ringmod, 1 for ringmod added to straight 4069 fuzz. A 2nd pole of that switch changes that 22k res. in order to equalize levels when flipping between sounds. 
The blended sound is fantastic.  Fuzz with wacky artifacts, sometimes harmonious, sometimes not. Very musically useful, your note pops out from within this filth.  I think the key reason this ring mod works with a blend so well is the the oscillator and your guitar signal sound so similar, they are created the same way -each a crushed 9volt square wave courtesy of the 4069 essentially. It doesn't sound like a guitar sound and a disassociated ring modulator running alongside.  Reduced the cap to GND at the output to a little more highs.
Thanks Freppo!
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on March 10, 2015, 05:11:00 AM
Cool :) Nice idea with the blend. I'm glad you like it!
/ Freppo
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Freppo on June 04, 2015, 06:50:18 AM
PCB's are now avaliable in my webshop. :)

www.parasitstudio.se (http://www.parasitstudio.se)

There are a few other PCB's avaliable aswell and alot more coming soon, so please check it out. :)
Cheers / Freppo
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Mr. Lime on November 15, 2019, 08:22:53 PM
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. :icon_rolleyes:  :icon_lol:

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

I know its a very old thread but there havent been a lot of discussions on XOR gates and I would really love to learn more about PWM with a 4070..
Could anyone point out, how the pulse width was modulated on the carrier frequency?

The links are all dead :(

Title: Re: The Corruptor - CMOS Ring Modulator
Post by: anotherjim on November 16, 2019, 04:27:16 AM
I think all the schematics for Parasit designs can be found in the build document PDF's.

I don't think you need Xor gates to make a PWM converter. If you AC couple a non-pulse wave into any CMOS input and arrange, via some resistance to the input a variable DC level (which can be another waveform!) then the logic switching threshold of that input will vary and the AC coupled wave can influence when the logic state switches.

Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Mr. Lime on November 16, 2019, 07:32:33 PM
Thans for the reply, Jim!

Sure there are simpler ways to archive PWM than with XOR gates but Im more interested
in having PWM control of the carrier oscillator. As previously mentioned in the thread, different pulse widths might soften the overall sound of the pseudo XOR ring mod.
The new corrupter circuit uses the XOR gate of a 4046 and the oscillator for modulation..

Is there a straight forward approach for PWM control for the 4046 oscillator that could be added?
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: anotherjim on November 17, 2019, 04:15:21 AM
I had hoped that the Inhibit pin of the 4046 might chop the timing cap charge allowing the PWM control, but no, Inhibit takes Pin4 low and resets the timing cap by forcing pin6 low.
It should be possible to chop Pin9 directly with a PWM signal letting the internal control Nmos be the chopper of the timing control current.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Mr. Lime on November 18, 2019, 11:47:13 AM
Freppo has mentioned in his article "octave up":

Quote
CMOS Workshop Part 4: octave up
1/3/20179 Comments
 
It's time for another part of the CMOS Workshop series. :)
This part will be about octave up circuits (aka frequency doublers).
Picture
The easiest way to produce a digital octave up is by using a Pulse Generator circuit, also called a Edge Detector. It generates a pulse at every high-to-low and every low-to-high logic transition, thus doubling the frequency.

It's a simple circuit and what used for the Arcadiator. There are several ways to do this. Let's have a look at a few examples and start with the easiest way that require the least amount of components.

You can click on the images for a larger view.
Picture
The top row shows the square wave and the bottom row shows the pulses generated with the edge detector circuit
1. XOR gate (CD4070)
The CD4070 is ideal for this purpose and require very little extra components.
Picture
XOR pulse generator schematic
XOR logic: For the output to go high, ​both inputs needs to be at a different state

​By connecting our square wave to both inputs and delaying one of the inputs slightly, there will be a brief moment when the inputs are in different states. At this moment the output will go high, thus creating a short pulse wave at the output every time the input goes high or low.

The delay is made out of a simple RC filter. It will round out the square wave, so that it takes alittle longer for each transition to cross the switching threshold of the logic gate.

(https://www.parasitstudio.se/uploads/2/4/4/9/2449159/xoroctaveschem_1_orig.png)

Quote
Here we can play around with different values for the RC filter. It will change the width of the pulses and the character of the sound. For C5 (C1 on the schematic) try a 4.7nF - 47nF value. For R5 (R1 on the schematic) try 10K-500K. In the 1B example I've replaced R5 with a trimmer and for convenience I chose another gate. The top greyed out part is the gainstage and schmitt trigger front end from the CMOS Workshop part 2 so you will have to check the other component values there.

Notice that the pulse width can get too narrow or wide for the octave up effect to work. As a rule of thumb you don't want the pulses to be too narrow because it will sound bad, and you don't want the pulses too wide because then it won't track properly on the entire fretboard.

So basically if we make R1 variable we get a pulse width control? It might utilizes the XOR gate of the 4046 but it's some sort of PWM, isn't it?
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: anotherjim on November 18, 2019, 05:06:31 PM
The pulse doubling that makes it sound an octave up is caused by the delayed input to pin 2 of the Xor. Remember, the Xor only outputs high when only one input is high. If you assume both inputs start low, pin1 sees the pulse goes high and the gate outputs high. Then the cap charges high and the output drops low because both inputs are high. Then the pulse goes low but the cap is still charged high so the output is high again until the cap is discharged and both inputs are low and the output goes low. So you get two pulses out for every single pulse in.

Yes, the smaller that R1 becomes, the narrower and more closely spaced the pulses will be.
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Mr. Lime on November 19, 2019, 06:34:11 AM
Thanks for the explaination, Jim!  :)

If someone would like to add a PWM control, I think it might be easier on the schmitt trigger fuzz side of the XOR input instead of the 4046 VCO.. (think of Escobedo's PWM)
This leads me to another question.
What's the prupose of the inverter infront of pin 5 of the 4046?
I see we want a gated oscillator which is quiet when the guitar is not played. The gate is formed by the schmitt trigger and the diode rectifier.
The inverter inverts the rectified signal so the gate opens for the 4046?
Can't we turn the diodes arround to ditch one inverter or does it have a buffering background?

(https://i.postimg.cc/qgMgGZfr/Corrupter-Ring-Mod.png) (https://postimg.cc/qgMgGZfr)
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: anotherjim on November 19, 2019, 10:24:54 AM
Pin 5 high stops the VCO. The inverter is buffering an envelope detector. When you stop playing, C6 discharges low and pin5 of the 4046 goes high and it shuts up, otherwise, it will keep running.

Title: Re: The Corruptor - CMOS Ring Modulator
Post by: Mr. Lime on November 20, 2019, 06:06:46 AM
I see, but is a buffer really needed here?

I ask because I would rather use a LM386 as sqaure wave shaper and a 40106 as schmitt trigger with no inverter left for buffering prupose..
Title: Re: The Corruptor - CMOS Ring Modulator
Post by: anotherjim on November 20, 2019, 07:32:34 AM
No, a buffer isn't needed, but an inverter definately is.