With two oscillators as inputs it does classic atonal ring mod sounds. It also works a treat on drums and if you have a mic it’s lots of fun doing Dalek impersonations.
It turns out that the carrier input doesn’t need to be that loud for erm… Dalek impersonations. So I added a pot to attenuate it - I wired it backwards though so I guess I have a chill-out knob now.
Good to know that a smaller capacitor will work. I’ve got lots of smaller value ceramic caps - 2.2uf seemed pretty large to me and the local electronic shop didn’t have any.
I’ll try adding them when the novelty of playing with it wears off!
As well as stepping up (increase) or stepping down (decrease) a signal voltage, transformers also have one very other useful property, isolation . Since there is no direct electrical connection between their primary and secondary windings, transformers provide complete electrical isolation between their input and output circuits and this isolation property can also be used between amplifiers and speakers.
Yeah, Schottkys have a low forward voltage which is good in this case. The germanium diodes Skala mentions do too. In fact by my measurements the 1N695 germaniums have a higher forward voltage than 1N5817 Schottkys. Skala does say of Schottkys:
Usually intermediate in price and forward voltage; but normally designed for higher power levels than are typical in an audio ring modulator, and that may have an effect on the sound.
or, I suppose, it may not. Anyway I bought some 1N695 for the RM I’m intending to build.
There’s some interesting I vs V curves for various diodes here
Too many hard-to-distinguish colors on the same plots, unfortunately, but you can kind of puzzle out what’s going on. Here are some germaniums along with 1N5817 Schottky (on the far left), 1N60 Schottky and an alleged 1N34A gemanium from eBay (right of that), the rather germanium-like BAT41 Schottky (the darker blue one starting at about 270 mV — I think!), and 1N4148 (greyish blue starting around 500 mV).
1N5817 is decidedly the lowest forward voltage of these, maybe the “best” for ring modulation in the sense of being closest to an ideal rectifier. The germaniums do have lower forward voltage than most silicon, but they (and the BAT41) also have a shallower slope for a softer cutoff, which some people like in distortion pedals. I plan on germaniums for my RM pretty much just because it’s “traditional”, maybe later I’ll build another with 1N5817 and see which I like better.
I got curious to see if precision rectifiers can and have been used to make RMs but on a quick google nothing turned up…
M0222 seems relatively hard to source and SP66 is expensive. (Small, though, which may be relevant if you’re building Eurorack.) I found the Triad Magnetics TY-141P appears to have specs similar to the SP66 and is cheaper (though it’s larger) and bought that from DigiKey though I have not yet built the module.
Added: Oh, and since the word “stripboard” is in the topic title: The TY-141P has pins that are too large for at least some stripboards’ holes, and spaced just a little off multiples 0.1". It’s close enough that you might be able to enlarge six stripboard holes to mount each, maybe. I get the impression many transformers are likewise stripboard-unfriendly.
