AW: Ribbon controllers and mark verbos naked with 303

Quinton Fulsom qfulsom at
Thu Jan 2 20:38:09 CET 1997

Well here my crappy $.02 worth
Since everyone is suddenly putting them on equipment and it seems as if the
su-10 by yamaha being
the first??? recently that is, that more than likely they are all getting
them from one source in japan.  I actually think it
may all stem back from the first designs from apple powerbooks e.g. 520 &
540 with their trackpads and if you want to get really hacky and shanky
(please don't misinterpret this as any sort of kinky advance especially mr.
verbos whom I have a pic of naked with his 303 he he heeee!!!!) the
trackpads that you see on notebooks now are being clearanced several places
on the web for $10.  I've been thinking of getting a spare and playing


> From: Haible Juergen <Juergen.Haible at>
> To: synth-diy at; WeAreAs1 at
> Subject: AW: AW: Ribbon controllers
> Date: Thursday, July 31, 1997 2:44 AM
> 	>The sensor outputs two voltages, one for pressure and one for
> 	>position.  The voltage range is roughly 0 to 5 volts.  The
> Position voltage
> 	>gets slightly filtered (just a couple of .01uf caps to ground
> to kill big
> 	>spikes) and then goes directly into one of the analog mux
> inputs.  The
> 	>Pressure voltage goes into the base of a small-signal NPN
> transistor,
> 	>configured as a basic transistor switch.  This transistor's
> output switches
> 	>between 0 and 5 volts, and is also read by the same mux.  
> This is good news. So if you once have this component, you're done.
> Would be very interesting to know what it costs. And: Maybe there are
> other synths that have longer ribbons, which would work in the same way?
> 	>I don't have a JP8000, but as far as I remember, its ribbon is
> not actually
> 	>"pressure sensitive", per se.  The ribbon's "Pressure" sensor
> is probably
> 	>there so the CPU can detect when you have placed your finger on
> it, and when
> 	>you have released it. 
> Sounds reasonable.
> >  It can then start reading the Position voltage, using
> > the voltage of your first Position as the "zero" point.  (It does work
> > this
> > way, doesn't it?)
> > 
> And the good news is that we can use this old Yamaha circuit (from the
> CS-80) to do this completely analogue. Great !!
> > I don't know how much the ribbon sensor would cost from Roland, but if
> > there's any interest, I could find out (I do Roland authorized
> > service).
> > 
> Please find it out !
> JH.

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