Breaking the rut with ring mod

[HeavyFog]

I find as of lately iv'e been building almost exclusively distortion in one form or another, both because a simple circuit thrown together can actually sound good with a bit of work, and because its in demand locally. I'd like to expand into something new and building a relatively simple ring modulator seems like a good place to start.

I see it going one of 3 ways:
-passive dual transformer style ring mod
(something like the first picture: https://en.wikipedia.org/wiki/Ring_modulation)
-Tremolo with the lfo beefed up to audio rate
-something completely different

I like the idea of the passive ring mod a lot but i am aware of its issues, (signals need boosting, ge diodes need to be matched, carrier bleed, adding active circuits negates the passive part of it, etc) but i feel it could be a bit of fun even if its not perfect. Would probably boost the input with a sho or lpb1 derivative and a simple oscillator or lfo could be made with a hand full of parts for the carrier. I'd imagine some sort of noise gate would be a good idea to cut down on carrier bleed. I think this is the most likely route for me to take as it probably the easiest to mess with and the simplest, but i still haven't made up my mind.

Not entirely sure what i would use for my carrier but i don't have much experience with LFOs and oscillators so if anyone has suggestions for anything relatively simple (trying to fit it all into a 1590g) that could be used as a carrier (or anything regarding passive ring mods in general) i'd love to hear it!

[nocentelli]

I'd imagine some of noise gate would be a good idea to cut down on carrier bleed.

I like the way the carrier is muted by the decaying envelope in Freppo's Sonic reducer circuit, the gate control works well

[ElectricDruid]

My experience is that you probably need some kind of noise gate with whatever type of Ring Mod you go for. The "balanced" part of "balanced modulator" is great in theory, but we know how much "theory" and "practice" have to do with each other (they're not on speaking terms, only communicate via notes passed to third parties, and the court's going to have to decide who gets the kids).

I've built OTA ring mods (both CA3080 and LM13700) and both have some bleed through. Not too bad if you play quietly, but nothing you could turn up loud and play live with.

So given that you're going to be building a noise gate to go along with this thing, why not use a LM13700, use half of it for the balanced modulator (ring mod) and the other half as a VCA for a noise gate? The ring mod bit is simple, just the OTA and an op-amp and a handful of resistors. Probably simpler than the passive one once you've added the buffers and gain stages and whatever else it'll finish up needing.

There's example in one of Ray Marston's books, page 55:

https://www.scribd.com/document/253630610/Audio-IC-s-Users-Handbook-Marston-pdf

Tom

[Fancy Lime]

I am absolutely clueless about ring modulators but I would think that it generally sounds like a good idea to be able to make the carrier signal follow the playing dynamics (to an adjustable extent), no? An envelope follower that controls the carries volume would be easy enough to implement and also be a noise gate for the carrier. I always toyed with the idea of building a ring mod with an envelope follower controlling the oscillator for extra weirdness but never got around to starting on this. Once you have the envelope, you might as well use it for both. Another strange idea: use a multiplexer driven by the (lowpass filtered) guitar signal to switch between the guitar signal and the carrier in such a way that it always ends on the guitar signal. The result is not a ring mod but may sound similar or at least also "interesting".

Cheers,
Andy

[Mark Hammer]

As I keep blathering on about, the "classic" passive ring modulator generally utilized a pair of sine-wave oscillators.  One can always supply a sine-wave oscillator for the carrier, but a guitar is not a sine-wave oscillator.  Ideally, then, one wants some sort of active circuit that can help shape the guitar signal into something closer to a sine wave, or at least with minimal harmonic content.

I will underscore this approach by noting that some cymbal simulators use ring modulation of noisy sources as a way of simulating what a cymbal does.  As a guitar player, you want something that sounds like trying to play a guitar that uses elastic bands, not a cymbal.  So whatever you use, you'll want a modulation source that can provide a sine or triangl-ish wave, and a means of rounding all the edges off the guitar signal.

[blackieNYC]

The anderton ring mod thread.
Try one you can tune out the carrier, though I do love to use the carrier tuned to the tune.
But I think the best way to use it is with an adjustable blend of a distorted version of the clean signal. 

[HeavyFog]

Been messing around with a schematic and here's what i came up with so far:



Il be boosting the input with a SHO to drive the ring mod and provide some nice drive and iv'e added a passive blend control after the SHO to control amount of ring mod at the output (assuming the ring mod wont invert the signal polarity and cause phase cancellation). There's also an external carrier jack that overrides the internal carrier when a jack is connected. Perhaps il wait until i get it working to add a noise gate to keep the complexity down for now.   

Haven't figured out the diodes yet but these  transformers look like they might work:
http://www.smallbear-electronics.mybigcommerce.com/transformer-1-1-for-direct-boxes/

All i need now is a simple, tune-able audio oscillator with a decent range that runs off 9 volts or less. The idea of tuning out the carrier with a pot sounds great, though i'm not quite sure how i could implement something similar to the anderton ring mod. I'm not overly concerned about the carrier as long as i can tune its frequency. Any suggestions for a carrier?

[digi2t]

From the "something completely different" category;

Logan 5 (derived from the Thing Modulator).

It's no longer on the Transistors and Beer site, but I have the info at home.

I built one along side a Digital Octave Fuzz in the same enclosure. Here's the clip (DOF alone first, and then with the L5 engaged);

https://www.soundclick.com/html5/v3/player.cfm?type=single&songid=10490290&q=hi&newref=1

[Mark Hammer]

Incidentally, when one hits the note which is the same pitch as the carrier, you get a great octave-up.  Indeed, Aphex uses that principle in their B unit to raise all harmonic content by an octave, feeding the same signal as both the X and Y inputs to a balanced modulator.

[allesz]

I really like ring modulators, I tried some from EH, wich was good, a dod gonkulator, bad distortion and a lot of carrier freq bleed through... then I got a zoom multistomp, wich as a digital ring mod that does the job.

Of course I also hit the diy route, in parallel with the above.

Like digi2t I went with a lm567 circuit, like the logan5, the thing modulator... and I remember also a similar project on codtone's site. Lm567 gets the work done with few parts, but the bleed through can be very bad; I ended up with a strong output filter and a different kind of bypass: the stomp switch also turns off the effects, I had it bleeding through ground even in true bypass. Maybe was just bad luck, but I tried also the cmos version of the lm567, but got still lot of noise.
digi2t clip sounds good (carrier) noise wise.... well, apart from terrible octave up fuzz and ringed out crazyness and distortion, of course 

Be prepared to do a lot of experiments, but it's a very entertaining chip to work with.

[HeavyFog]

Just had an interesting idea for that incomplete ring mod circuit i posted above. What if i split the output of the SHO a third time and sent that signal to an effects send/return and used that branch as my carrier, giving more possibilities by letting me add new effects into the "carrier" path. I know this would be different from the classic ring mod sound but i think it could be neat if it were to work.

Thoughts?

[allesz]

It can be a nice idea. But the problem is wich carrier generator to use.
Reading around it seems that an atari punk console has a too strong output.
Maybe a 555 toy organ would be good.

I wonder if a single bjt oscillator would work.

[ElectricDruid]

You can always scale an output down a bit if it's too strong for a given circuit. And a BJT oscillator would work - why not? Anything that produces audio signals will work.

The question is "what sounds best?". Mark Hammer suggested earlier that he preferred signals with less harmonics so that the output doesn't turn to total mush quite so quickly. For this, something like the Atari punk console is right out, and something like a triangle wave or (even better) a sine wave is right in. Sine wave oscillators are an entire area of study in their own right...
Personally, I'd probably write a sine/sine+octave generator in software and put it on a PIC, since that's what I do with pretty much everything . Maybe I should design a ring-mod...add it the backlog!

Tom

[allesz]

Nice to know EDruid.

If it was me, but I don't have the transformers, I would try one of my bjt obsession: the negistor.

[allesz]

This discussion made whant to try out some ideas: would it be possible to substitute the transformers with a bjt phese splitter? Like in the green ringer, for example.
I wonder how, and were put a carrier frequency...

[vortex]

I picked up a Maestro Ring Mod many years ago.

It's hard to put in words how just how wicked and wonderful the Maestro is.

When I hear 'other' ring mod pedals, (haven't played the Moog...), they just don't dish out the sonic weight of the Maestro.

The MC1495 ic's are obsolete but pop up here and there. One day I hope to build a clone, It would be cool to figure out a work alike with a simplified power suppy etc.

[Ben N]

Futurlec has MC1495s. Pricey, though.

[ElectricDruid]

Futurlec has MC1495s. Pricey, though.

Don't bet on it. Futurlec are a bit hopeless at taking stuff down from their website. Notice they don't actually list a stock level:

http://www.futurlec.com/Motorola/MC1495Lpr.shtml

I once ordered 200 x CA3080 OTAs at the point at which they were getting to be hard to find and Futurlec were one of the few places that listed them. After a couple of months with no chips showing up, I started hassling them to find out what was going on. Several emails later it transpired that they didn't actually have any and they eventually refunded the order. I was pretty miffed, since they'd been sitting on my money all that time and didn't bother to tell me that they didn't have any and weren't actually likely to get any, and I wasted weeks waiting for something I could have found somewhere else.

T.

[bluebunny]

Ack!  Futurelec...  "Future" is like "tomorrow" - it never happens...   

[Danich_ivanov]

I made a tremolo pedal recently, and to my surprise it does a really cool ring mod, the only problem was constant noise from the frequency, so i added envelope detector to it, which chokes the depth control when guitar is not playing, and it works very well now.