The Corruptor - CMOS Ring Modulator

[Freppo]

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:  


I found some usable setting at about 4:20, so you can skip ahead  
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?



cheers
/ Freppo

[anotherjim]

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.

[Freppo]

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
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?


I have to run to work now..


cheers / Freppo

[peterg]

Freppo - I'm going straight to PCB with this. Is this schematic confirmed?

[anotherjim]

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
 

[Freppo]

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...

(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

 

[peterg]

Thanks Freppo

[digi2t]

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?

[glops]

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.

[Freppo]

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  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.

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

[digi2t]

How about adding this to the front end?

[anotherjim]

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.

[Freppo]

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.

How about adding this to the front end?

Hopefully a booster at the frontend won't be needed now 

/ Freppo

[digi2t]

Awaiting your test results before I commit to vero.

[Freppo]

Awaiting your test results before I commit to vero.

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


Full size version: 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.  

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

[anotherjim]

COOL 

[Jamforthelamb]

:crosses fingers for vero layout of this one:
Seriously man, sounds awesome!

[peterg]

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?

[Freppo]

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?

[peterg]

It adjusts the oscilllation but doesn't make it go away. I'l try some other 4069s.