real ringmod

fluxmonkey · Joined: Jun 24, 2005 Posts: 708 Location: cleve

finished up a build last nite of a dual real-ringmodulator module. added buffers to the ins and outs using a pair of CGS70 mixer/inverter blocks, with bit of makeup gain (RGs at 180k instead of 100k). WOW, these things just rock! these are the real deal, like the Barron's used on Forbidden Planet.

i brought the ins/outs of the other 2 inverter sections to the front panel as well, always handy to have. all in 1/2 frac.

thanks ken!

b

numbernone · Joined: Aug 16, 2006 Posts: 477 Location: new york city

Brilliant, I have a pair of these too, with the old computer diodes... been wondering how to hook em up.

ericcoleridge · Joined: Jan 16, 2007 Posts: 889 Location: NYC

I'd love to hear some samples of this ring-mod. I've read a lot of praise for it, and I've always wondered what it is that seperates it from a typical ring mod (1496 or 633 types, for instance). Do you have any recordings? Very Happy

flies · Joined: May 20, 2008 Posts: 33 Location: NJ

there are some samples of this (other) passive ring mod available here http://www.analoguehaven.com/makenoise/moddemod

jnuaury · Posted: Wed Aug 13, 2008 12:40 am Post subject:

and bridechamber is selling 2 tranformers and 4 matched diodes for $10 for the cgs ring mod

so you can do a nice cheap and easy ring mod on stripboard if you want

ericcoleridge · Joined: Jan 16, 2007 Posts: 889 Location: NYC

Yeah, I also like the wave multiplier+real ring that they sell, thinking of trying one of those. But I already have a couple ring mods, and don't really need another. But I am curious to hear this one.

Adam-V · Posted: Wed Aug 13, 2008 7:23 pm Post subject:

I wonder if you could replace the diodes with op-amps set up as ideal diodes?
I also wonder if it would be worth while?

Cheers,
Adam-V

otherunicorn · Joined: May 11, 2008 Posts: 136 Location: Australia

Adam-V · Posted: Sun Aug 17, 2008 7:41 pm Post subject:

Good point. I was thinking more in terms of signal loss, but this is probably best compensated for with buffers as mentioned in the initial post.

Cheers,
Adam-V

certain2 · Joined: Nov 21, 2008 Posts: 5 Location: yorkshire

I'm not sure I understand this. The standard advice is to use germanium
diodes rather than silicon since they have a turn on voltage of 0.35V rather
than 0.7V, consequently silicon cause some clipping and distortion.
RF enthusiasts building balanced modulators use schottky diodes
which have an even lower turn on ~0.25V to minimise distortion. Avago
(ex agilent ex HP) make matched schottky quads specifically for this
application. Has anyone tried these in a real ringmodulator in an
electronic music context?
Or is it that germanium diodes give "just the right amount" of distortion?

blue hell · Posted: Fri Nov 21, 2008 1:12 pm Post subject:

Welcome certain2,

germanium diodes also have a softer knee I think, which could play a role too. But it would be pretty cheap to experiment a bit that Wink

LektroiD · Posted: Tue Jan 06, 2009 7:16 pm Post subject:

How can you spot a germanium diode?

I have some ancient looking diodes here that I've picked up over the years, such as these metal cased diodes, that are about twice the thickness of an average resistor, and simply have the number 4 stamped on them. Maybe someone could shed some light?

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blue hell · Posted: Tue Jan 06, 2009 7:54 pm Post subject:

OMG ... that might even be selenium Laughing

When you put 'm in series with a 1k resistor and connect that to a 9V battery you can measure the voltage over the diodes, GE should give 0.3 .. 0.4V, SI 0.6 .. 0.7V and for SE I really wouldn't know. When you measure about 9 V please reverse the battery.

Sebo · Joined: Apr 27, 2007 Posts: 564 Location: Argentina

Hi:
I have some questions about the diodes.
I read they have to be old germanium diodes, but not any specific. Any
rules about that?
Could 1N60 work?
Some people say that used old computer diodes, from what computers?
(early PC, Commodores, older?).
Thank you.

andrewF · Posted: Wed Jan 07, 2009 7:50 pm Post subject:

I have used 1n60 in a RRM - no problems
Probably any old ge diode will be fine.

I think the old computers Ken refers to are REALLY old, from the 60s.

Uncle Krunkus · Posted: Wed Jan 07, 2009 11:33 pm Post subject:

I've got some old black glass ones (an OA74, an OA79 and an OA85) I've also got some "new" Ge diodes of various types. Do they have to be the same type? If so, I think I'd start by experimenting with the new ones, but I'd like to see if the old ones will work.

blue hell · Posted: Thu Jan 08, 2009 3:53 am Post subject:

Sebo · Joined: Apr 27, 2007 Posts: 564 Location: Argentina

I will try 1N60 first.
Thank you.

Adam-V · Posted: Thu Jan 08, 2009 5:37 pm Post subject:

Uncle Krunkus · Posted: Thu Jan 08, 2009 6:18 pm Post subject:

Is it just about overcoming the small forward voltage drop in order to send top and bottom parts of the wave in different directions, or does the linearity/non-linearity of the diodes have some impact on the operation?

LektroiD · Posted: Thu Jan 08, 2009 7:41 pm Post subject:

Which transformers should I use for this?

Are any of these any good:
http://www.maplin.co.uk/Module.aspx?ModuleNo=3709

Adam-V · Posted: Sun Jan 11, 2009 2:40 pm Post subject:

scriptstyle · Joined: Jan 22, 2008 Posts: 250 Location: nj

frijitz · Posted: Tue Jan 13, 2009 8:47 pm Post subject:

Lofi Ninja · Joined: Oct 25, 2008 Posts: 143 Location: Jupiter

Hi guys..

Found this thread last night, and I imediatly threw togheter a passive ring mod..

Diodes are un-numbered silicon ones, the ones that are glass like with the orange stuff inside..

Transformers are nr. 273-1380 from the shack..
Impedance: 1KHz, 1V, 0mADC
Input:1Kohm 10%
Output: 8 ohm (loaded)
DC resistance (input): 70ohms 20%
DC resistance (output): 0.62 20%
Frequency response: 300-10,000 Hz 3dB

I've never had my hands on a ringmod before, so I'm not sure if it's working very well, but I like the result very much..

BTW. Matching diode pairs, in this schema, top pic,
http://www.cgs.synth.net/modules/pic/schem_cgsrr.gif would the pairs be the ones that are parallel, and the ones crossing ? Or is it one of each per pair ? Thank you very much!

I will make a video for you now so you can hear it in action Very Happy