I realized a while ago a Real Ring Modulator (CGSRR) of Ken Stone in a box for my hacked machines, and today I would like to make a module of it. I know that my passive version with only the transformers and the diodes, lowers the volume of output enormously.
Without realizing the version (always by Ken Stone) Active Real Ring Modulator (CGS67)
but just re-amplify the output signal.
would this schem, without the potentiometer and with a trimmer of 100k instead of the resistor of 67k can do the trick
thanks !
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Try it in a breadboard and see, Or…Have a look at this as an alternative:
It’s all cmos logic so negative voltage signals would probably not work, but one stage of the 4070 mixes frequencies. If you add another oscillator input or internal oscillator to modulate it, you may get the effect you’re looking for.
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yes thank you, I know CMOS Bell I made this module, but it’s logic it’s not what I’m looking for. the real ring modulator is really better (original 1963) and I would really like to re amplify it, as you say I will do some tests
thanks again
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Yeah, that circuit should work. It’s a voltage buffer, an attenuation pot (LEVEL), and a non-inverting amplifier set to 4× (1+67/22 = 4). Change the 22k to 10-12k and the 67k (that’s an odd value) to a 100k trimmer, and you get a nice 1-10× amplifier.
If you only need amplification, you can drop the attenuation pot (and the buffer too, but unless you have a pile of TL071s lying around that’s not really worth the effort).
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thanks a lot Fredrik !
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like this ?
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Yeah, that should work (assuming you have a TL071 that is, if you only have TL072 in stock you might as well use one of those and keep the buffer, since you shouldn’t leave inputs floating).
Talking about floating, if you’re using an input jack you may want to add a 100k resistor between input and ground, to make sure the + input is well-defined also if nothing is plugged in.
PS. The real ring modulator was invented in 1934, as a slight simplification of a design from the late 20ies 
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yes i have tl071,
no i don’t make a input jack (the real ring modulator will be connected directly to the input pin),
so for pins 1 and 5 I have to ground them?
thanks for history 
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This thing will also amplify a DC-input voltage. If that is not what you want, add an electrolytic capacitor of say 47 muF at the input (plus to pin 3) and output (plus to pin 5).
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thanks a lot Jos ------
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I found this one in an old folder today too.
I don’t recognize the 633JN but I thought I’d include it if you were interested.
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This is the last part I need for my mfos ring mod. Can’t find it anywhere for less than 10$
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633JN is just someone being confused by how chips are named; the manufacturer code is AD633, and it’s still in production so no need to buy “fake” ones off AliExpress 
(the full product code is AD633JNZ if you want through-hole, the non-RoHS JN variant is obsolete)
EDIT: “fake” in quotes because odds are they’re actual AD633s that’s been recycled/repainted, a process that’s sometimes spelled “brand new” in AliExpress/eBay land.
EDIT 2: More on fake multipliers: How to multiply currents: Inside a counterfeit analog multiplier (fake AD633 turns out to contain the die from older simpler chip, instead of the expensive laser-calibrated version.)
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But more than ten bucks each at Mouser. Whatever they’re selling on AliExpress, it’s a small fraction of that price.
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I’m seeing about $6.50 +shipping (!) from US sources (allegedly) on eBay. Most of the time I think the NJ sources turn out to be legit. Some of the CN sources are down at ~$2, but again, caveat emptor. Mouser-style supply houses are going to have the same or higher shipping than quoted on the bay though, so it might still be a good way to go.
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They’re around $10 from the manufacturer (for a minimum order of 50 pcs), so if you buy them for $2 you’re not getting a new chip. If you’re lucky, you’re getting a recycled chip from someone who claims it’s new because the guy they bought it from said so, but the chip still kind of works. If you’re unlucky, you get something else.
This whole video on “fake” chips is worth watching, but especially the bit between 2:30 and 5:00:
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Redraw the center part like this
and you can see why it’s called a ring modulator.
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yes of course
i finished my built today
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Are those germanium diodes? Which ones?
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