Ring (and/or Balanced) Modulation for the modulator masses

[lordgalvar]

Big moog.

Diode ring is at the top of the page.

Feed it whatever.

RMA, DBA, ADD, I think Studio Electric (iirc) are production diode ring based pedals.

Another note about bleed: I’ve noticed some carriers have greater amplitude in LFO range and less in audio range. That could lead to some imbalance too (but is potentially better for results at-the-ear…because of its frequency range). Some really hot lfos/oscillators (like 10vpp) will take over and basically sound like a bad full resonance filter (sine wave) slightly modulated to be in audio range (guitar or whatever at maybe 0.75vpp).

As long as the carrier and modulator are close, ain’t nothin’ to fret. This is mostly diode rings and some older stuff like that siemens u101 (ill look for mine to fond the actual number later) or something (which looks kinda like a carlin style transistor based thing in a metal can).

[cosmicevan]

So I've been out of the loop for a while on ring mods. What's the best ring mod pedal around these days and why is it still Randy's Revenge?

I have been extremely impressed with Pladask Elektrisk's FEBER.

[Dandolin]

the feber is rad

as for RR, for the vast majority of guitarists (as distinct from the smaller subset of dedicated noiseonauts) that one is already at the pareto optimum, so i doubt anything ever really knocks it off the podium, tho others may eventually try to squeeze up on there with old Randy.

my personal grail choice remains the RMA, hoping this is the year one teleports into my world....

[crochambeau]

my personal grail choice remains the RMA, hoping this is the year one teleports into my world....

I have been gripped with a massive stupidity of the brain, etc. and my throughput is most definitely crippled. That said, I'm working toward that goal (and many like it).

Designing a ring modulator without noticeable bleedthrough was as hard as anything I have ever done - often people put a noise gate in. Note that any mains hum on the signal input will modulate the carrier & be very obvious, giving the impression of bleed through. Incidentally, I found that even when the hum-modulated carrier output was buried in the noise floor in the scope image, it was still audible. I hadn't expected to be able to hear something that I couldn't see.

I can concur. I'm toying with some concepts still that may survive into the Polybius, but it's been a staggeringly convoluted path and I'm expecting the culmination of this particular line of travel to overshoot market feasibility. I'm still going to see it to the end, mind you. Such is the product of obsession.

[Dandolin]

the stream will converge when the time is ripe 'til then, i'm honing my own limping brain to be able to comprehend whatever it is you will have wrought

[Chankgeez]

Yeah, was gonna say, Monobius is an instant modern classic.

The garden-variety Randy's Revenge is still a fave though.

Big Moogerfooger is difficult to beat in terms of functionality.

[qersty]

hmm i say, hmmm
https://reverb.com/item/39418082-mono-d ... ator-pedal


"The Gilbert Cell Freq Mod is a totally discrete (transistorized) frequency (semi-)inverter pedal. A Gilbert cell mixer is a type of analog multiplier implemented here in its original transistor form. When overdriven, the cell produces its own saturation effect in addition to the frequency inversion that is carried out by multiplying the input guitar signal with the internal discrete oscillator.

(For reference, frequency inversion shares some similarities with ring modulation).

We are classifying this pedal as a frequency semi-inverter because the internal modulation scheme allows for bleed-through of the original signal dependent on the depth control.

Additionally, when the depth control is at maximum the internal carrier oscillator is partially modulated by the input signal which allows for audio-rate modulated frequency inversion."

So can i get a graphic on what this does?

[lordgalvar]

It's a like a tremolo that works on both sides of zero using transistors. Or two VCAs, one changing volume on the positive side of the wave and the other on the negative side.

At maximum depth, the input signal changes the rate of the LFO a bit (which, because the instrument is audio rate and the LFO is slower, kind of looks like waveshaping. If the Oscillator is faster than the instrument, it would look more like the rate changing over time). It adds harmonics and possible heterodyne.

The bleed and stuff is just noting that it is a very basic design that can be thrown out of balance and never really gating the carrier oscillator.

It's a fun pedal. Just some dialing in for instrument dynamics (and readjusting if using something before or changing pickups or something) to get more classic "ring mod" type sounds.

[Dandolin]

yeah - this sounds very cool, lg! also interested in their integrator pedal

[lordgalvar]

The integrator is kind of subtle until you to it off and realize it added some fundamental goodness. Kind of like a strength or body. It actually works really well with the Gilbert cell because it kind of controls dynamics.

[qersty]

so it modulates the amplitude of the plus an minus of your waveform seperately? i tried looking at a vid explaining gilber cells but got to tired

[lordgalvar]

Your input signal/instrument changes the frequency of the Oscillator/carrier. That part is independent of the Gilbert Cell mixer.

The +/- 4 quadrant signal multiplication via the gilbert cell is just where the two waves come together. Just a different way to accomplish balanced modulation/ring mod (like a passive diode ring or parallel op amp vcas or something). Gilbert Cell is just a way to mix two signals. I guess you could look at it like signal 1 is changing the volume of signal 2 and signal 2 is changing the volume of signal 1. At audio rates, it changes the harmonic content but at LFO rate, it is like a tremolo.

The one in this pedal is discrete but you can get a Gilbert cell in an IC (like that siemens u101 or whatever i was talking about last page or something).

[crochambeau]

Gilbert Cells are cool, I'm glad someone is making them because that means I don't have to .

so it modulates the amplitude of the plus an minus of your waveform seperately? i tried looking at a vid explaining gilber cells but got to tired

No, it does not separate anything.

Imagine a single stage as a teeter totter. Each side of the teeter totter has an input, nearish to the center, and each side has an output, nearer to the extreme ends that enjoy the most travel.

Still with me?

For brevity, we're going to connect one of the two inputs to ground/zero volts. For the sake of this explanation, let's just shift the pivot point over to that input and let the entire teeter totter swing around zero volts. Dig?

So when I push the *active* input up, that side of the teeter totter swings UP much farther, while the other side swings down.

All I have done so far is to describe a simple differential pair...

What the Gilbert Cell does is it duplicates the differential pair, making two, and connects the two "UP" sides together to form one output, and connects the "DOWN" sides together to form another output, and then places each of those differential pairs on one of the two outputs of a third differential pair.

So to round back to our teeter totter analogy, we now have a foundation teeter totter with two more teeter totters where the seats would go (and those teeter totters have their "seats" connected together on each side.)

I promise this is going somewhere.

The foundation differential pair is our carrier/CV section. We can ground one of its two inputs to simplify the explanation, so any voltage in is going to make one side (carrying a diff pair) go UP, and the other side (carrying a diff pair) go down. The magic is what we do with the inputs of the two "flying" diff pairs. These are cross connected such that applying a positive voltage on one input will make one flying diff pair push up while the other pushes down.

Therefore (in a balanced version), signal at the input cancels itself out, unless there is also signal pushing on the foundation. Furthermore, the master output is taken from the connected outputs on the two ends of the lower differential pair, and so unless there is "signal" up top, the lower output is also nulled (-5 plus +5 equals zero).

Since this is such a topsy turvy circuit, is is entirely possible to go through zero with it, which is to say that an input can be polarity matched to the output, and then swing to no volume level and ramp back up in volume as a polarity inverted output. Doing this shift at audio frequencies is where the Ring Mod application sits, but that is just one application for a multiplication cell, which is what Gilbert does.

[K2000]

I don't want to derail the thread, but the Mono Division pedal line looks interesting. But looking at their Etsy and Reverb pages, there are almost no sales in their history. Maybe most of their sales were direct. But no reviews and no demos, except the 60cycle Hum Youtube video. I hope there will be more demos and reviews at some point.

[lordgalvar]

I bought direct. Have triangle integrator and gilbert cell. They are great. Good experience buying from mono division.

I like the triangle integrator better of the two. It’s a welcome different kind of synth sound for guitar. Kind of like an old octave pedal but in someways more natural sounding synth some kind of synth oscillator sound. It’s kind of hard to describe.

Gilbert cell is good. Limited carrier range. Needs distortion around it.

For science:

Ravish sitar as sympathetic carrier/lead modulator sounds awful. Nothing more to look for there. I think the noise buzz takes over and it doubles that frequency which makes it sound like weak noise. Not in a good way.

Pitch fork plus aux as carrier/main as modulator is great. Like one is dropping pitch down and the other up in some intervals. It does have some extent of that pitch fork/ehx shift sound, but it can be minimized with the right pitches. Haven’t explored xmod in this setup, but I expect some fun. Should be a useful carrier overall though: mix out the oscillators or dry and use aux to send different signals for some routing possibilities and presets to simplify it a bit.

With a moogerfooger (or any with carrier out and in), route the aux out to an a/b switch and the carrier from the moog to the other in. Drop out shift one or use presets and cycle through some carrier changes but still able to go back to the original free running oscillator.

I though the ravish might work in the same way, but it sucks.