passive ring modulator questions.

[KorovaMilkBar]

hello everyone, i was wondering if anyone had any links to a wiring schematic or a picture of a the circuitry of a finished ring mod. i was wondering if they are indeed easy to make and just wanted know more about how it is done. thanks!

[Taylor]

The passive ring mod is indeed very, very easy to make. Here's the schem:

http://tingilinde.typepad.com/photos/uncategorized/ringmod.jpg

Only 6 components, and if you use a matched diode array (which is perfect because the carrier rejection will be much better), it's only 3 components. Without question the most weird for the least work.

BUT,

there are some serious limitations in the passive RM. First, there is no built-in carrier. You will not be able to plug a guitar into the circuit above and get anything out - you need to add an oscillator. You can plug a synth into one of the inputs and tape a key down, or you can build an oscillator. Besides that, you will probably need to buffer and possibly boost your guitar input. You will also probably want to add some facility for mixing your clean signal in, since without that, many people find ring modulation too bizarre to be usable.

Once you get done with all that, your "passive" ring mod is no longer passive at all. The Lovetone Ring Stinger, for example, uses the exact same scheme as in the schematic above - 4 diodes and 2 transformers - to do its ring modulation, so it starts out as a passive RM. The vast majority of the circuit is not in the ring modulator itself, but in the oscillator, LFO, mixing, and filtering.

So, although it looks very simple, the passive ring mod needs a lot of other circuitry to be useful to most people.

[KorovaMilkBar]

cool thanks, ya i know about the whole theory of ring modulation and the most basic ring mod is 2 carrier inputs in, and the modulated (combined) output. i do have some diodes laying around (those small red ones that come from radioshack) so i did just want to build a quick one and see how it comes out. i would probably just use the thing for background noise, quick weird sounds, or some quiet ambient weird sound if i were to record with it. i would also like to see how it sounds with certain instruments combined with vocals. maybe later i will try to build better curcuits into it for better sound.

thanks again!
mike

[Taylor]

Just beware that when you put a complex sound into both inputs, you're not just adding and subtracting the fundamental notes to/from each other (say, singing a G and playing a C), you're adding and subtracting all the harmonics from both instruments to and from each other.

The end result doesn't sound so much like the robotic or metallic sound we associate with ring mods, it usually sounds more like harsh noise. If that's what you're going for, there's nothing wrong with it, but you could probably get the same thing by just using a distortion pedal.

To get the "usual" ring mod sound, you need to modulate an instrument with a simple waveform with few harmonics. The sine wave is the usual choice because it has no harmonics at all.

[soggybag]

This circuit makes a good octave up. By using the same signal as both input and carrier. You probably need a buffer on input and output to push the signal through the two transformers and diode ring.