Passive Ring Mod Kit

[moosapotamus]

I picked up a couple of these and thought I'd pass it along... they're pretty damn nice.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7318739300&rd=1&sspagename=STRK%3AMEWA%3AIT&rd=1
Slightly different design than the standard diode ring type of passive ring mod. Real nice sounding with good carrier rejection and lots of possibilities. Would be fun to experiment... add a couple VCO's, an LFO w/ variable waveforms, a mixing stage, hmmm... could get kinda freaky cool!

~ Charlie

[Wild Zebra]

pretty sweet,  looks like it would go nice with the sound lab
everyones been chatting about

[ExpAnonColin]

Right, excellent that he is hand matching everything, and thanks for the headsup, but...

why the alternate design?  I don't get the point behind not using the standard diode ring pattern.  I mean, aside from the fact that he thinks that his "Unique differential circuitry results in high degree of input signal (carrier and modulator) suppression.", why does it work as such, if it does?

-Colin

[moosapotamus]

why the alternate design?

Interesting... I don't really know why. You should write to the guy if you're interested. He responded to my questions same day and was very forthcoming.

I don't know anything much about why it does what it does, and I have never tried the simple diode ring design either ( http://www.synthfool.com/ringmod.html ), so I can't make any comparisons. I just went for it because the transformers were already spec'd and the diodes all matched.

Turns out that it sounds good, so I just thought it seemed like the kind of thing folks here would find interesting... like those new/old stock populated phase100 boards that were on eBay a while ago - I nabbed a couple of those, too. :wink:

Anyway, the design is apparently based on an old RF modulator circuit that was lost and somewhat forgotten about in some old textbook or something. The transformers are on both of the inputs, instead of on the output and only one input. It doesn't matter which input you plug the carrier or modulator inputs into. They're interchangeable.

To me, it seems like the quieter of the two inputs sort of becomes the carrier. You can manage carrier suppression by adjusting the input levels appropriately, turn the carrier down and the modulator up. There's a lower threshold below which the carrier cuts out and the total output drops off. I definately need to play with it a lot more, but it's pretty cool so far.

~ Charlie

[ExpAnonColin]

Hm, interesting.  His response to my email was that it was "differentiable", just like he says in the auction.  I guess if I ever had actually gotten around to fooling around with the passive ring mods I might buy one and make a comparison, but I never got around to getting transformers!

-Colin

[soggybag]

I wonder if you could make and Octave by feeding the same signal into the signal input and carrier input?
What kind of input signal can you use with it? Did you plug your guitar directly in or do you need to amplify the signal?

[moosapotamus]

The way the PCB is done, if you plug into only one input you get it going into both, and the output will be double the input frequency... technically, ocative up. Actually sounds like grungy octave up, kind of similar to the green ringer sound.

It's set for line level input, so if you want to plug a guitar, you should preamp or boost it.

~ Charlie

[radio]

Hello
Thanks "Moose" thats just in time

I was about to order the parts when you came up with this

need one for a kind of octaverx clone(personnel use!!)

and some synth experimentations but I was told

temperature diffs where bad for Ge ,I shall see.

That ll be a faast Prooject

Greetings JMErnzer

[shawn]

Or you could order a completed item here:

http://www.cgs.synth.net/modules/cgsrr.html

As well as a few other goodies.

[Pedal love]

I use to build circuits like these, passive types with diode bridges.pl

[puretube]

you can find currently produced new quad-schottky diode-chips at F*rnell - either individual 4 on a dye, or internally wired as RM...

(Yes: "schottky"! :wink: )

[radio]

Puretube

Does Schottkys "resolve" the temperature problem

or is it the less voltage loss that makes them the

better choice,maybe more compact(chip versus quartett)?

Greetings from Old Europe with 4 american visitors

(delaware til15th Virginia til 1ofJune total 5)

[object88]

What is the temperature problem?

[brad]

I wonder if you could make and Octave by feeding the same signal into the signal input and carrier input?

Zvex made a passive pedal called the "Earth Saver Octave" back in the day, so I guess it must be possible somehow.

you can find currently produced new quad-schottky diode-chips at F*rnell - either individual 4 on a dye, or internally wired as RM...

Yowza.  I've actually got some of those.  Is matching necessary?  I thought this project might be a good way of using up bad Ge Transistors when I first saw it!  

*edit* I guess you could just match bad Ge transistors that have the same voltage drop.

[puretube]

i haven`t tried them, nor seen a datasheet;
but the fact that they`re "schottky" tells me: lodrop (good for passive circuits...),
and the fact that they`re 4 on 1 chip tells me: perfect match;
(oh yes, and no temp-diff, FWIMC)...
:?:

[brad]

ok, thanks puretube.  I'll have to give it a go on the ol' breadboard if I find some transformers.

Moosapotamus's idea of using an LFO ect for the carrier sounds very Moog!  

[brad]

just what kind of transformers are needed btw?

[vortex]

Hey! I just got the kit in the mail yesterday and built it tonight. A nice kit! Solid circuit board, clear instructions, good parts and matched diodes. Simple and fast build.

I am fortunate to have a Micromoog for the "Carrier" which it does with style.  I am using a Mosfet boost to crank the input from my guitar, this is necessary and works well too.

I'm still not sure what extra circuits I will add when I box it up. The boost for sure, possibly an internal oscillator if I can get an acceptable result from the unijunction transistors I have.

Any thoughts how I might approach the blending of the straight and modulated signal?

[EATyourGuitar]

NECRO BUMP! all these links are dead and this was some lost and forgotten differential ring mod! I want that. anyone have the schematic or know who the guy is? or is it lost forever.