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Subject: Re: Tech Question Regarding CS-80 Ring Modulator

From: "elie" <elieman@...>
Date: 2012-01-08

Re: Tech Question Regarding CS-80 Ring Modulator



Thanks! The retrofit board would be great for a physical substitution whenever
it comes to fruition, otherwise I followed your immediate suggestion and looked
at alternatives...

Since my mods are still at the prototyping phase, I bread-boarded a Thomas Henry
related Ring Modulator Design utilizing an XR2206 which has the Triangle/Sine
VCO and built-in Multiplier.

I tested it in my CSY-2 synth/organ by feeding the separated VCO output to the
Multiplier Input (other side is occupied by the internal VCO of course).

Since the Henry design provided an Oscillator Voltage Controlled Freq. terminal, I took a tap
off the CSY-2 'after-touch' circuit and summed that with a feed from the CSY-2
VCF envelope generator output and slow oscillator (LFO) with some very pleasing results!

By providing gain, offset & polarity adjustments to the respective Ring
Modulator VCO modulation sources (in combination with setting a
default/static VCO frequency) there was maximum flexibility to produce the whole
gamut of Ring Mod. styled effects...very cool!

Thanks again for the suggestions, please let me know if you have anything to
add, especially if you have any specific opinion of my having used the XR2206
vs. the UA796 (MC1496 equivalent part?) as found in the CS-80 in combination
with the XR2206 to provide the VCO functionality.

Also, I believe the CSY-2 VCF envelope generator source I used is exponential,
but I'll have to confirm.

Elie

--- In yamahacs80@yahoogroups.com, The Old Crow <oldcrow@...> wrote:
>
> You do not really need the 159/151 to make an attack-release EG just
> for a modulator. Google for a "attack release envelope generator
> schematic." The IG00150 is another part I plan to make as a small
> retrofit board. --Crow
>
> On 11/18/2011 3:35 PM, elie wrote:
> > Thanks for the insight, I'll have to come up with a suitable substitute - turns out the VCO part is not available - the part I had my eye on has +/- a zero vs. the proper part...
> >
> > http://www.organforum.com/forums/showthread.php?18878-latest-OrganGrinder-list
> >
> > I'll get there eventually!
> >
> > Elie
> >
> > --- In yamahacs80@yahoogroups.com, The Old Crow<oldcrow@> wrote:
> >> The 159 is a linear timing/voltage sequence generator that uses the
> >> exponential input of the 151 to create the exponential sloped envelopes.
> >>
> >> Crow
> >> /∗∗/
> >>
> >> On 11/15/2011 9:16 PM, elie wrote:
> >>> Hi, I'm implementing a CS-80 Ring Modulator design on another Yamaha Synth. No problem getting the Modulator& buffer amps, VCO chip but the VCA (IG00151)and Envelope Generator (IG00159) are not practical to purchase.
> >>>
> >>> My question is if the VCA and Envelope Generator are Linear or Exponential in function?...not sure if the service manual might answer that so just in case anyone knows?
> >>>
> >>> Thanks!
> >>> Elie
> >>>
> >>>
> >
> >
> >
> > ------------------------------------
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