Yamaha CS80

From what I've read, the old expression pedal was the FC-3a, which was 
also used for other synths, like the GS1/2, DX-7, etc.  The pedal input 
a voltage on the sleeve (-15v in the CS80) and output a voltage on the 
tip of the plug.  It did this with a light bulb / shutter / photocell, 
but there's nothing magic about this.  What's kind of weird is that this 
voltage is buffered and used to drive an LED light, which controls the 
signal feeding the main volume knob (all on the PRA board). I don't know 
why the used an LED / photocell as a VCA when there are a billion 
IG00151 VCA chips all over the rest of the keyboard.

Anyway, Yamaha now sells the FC-7 pedal.  It just uses a potentiometer 
(probably with a weird taper to match the old response) instead of a 
light/shutter/photocell. However, the Yamaha manual ( 
http://img3.musiciansfriend.com/dbase/pdf/man/m_151552.pdf) says it's 
compatible with the old FC-3a.

 David

rj krohn wrote:
> yes, that would be great, gustavo. thanks alot-any leads you could provide(or a diagram would be awesome) would be hugely helpful. i have yet to find anyone who is using a current market expression pedal on a cs-80, so at this point, your lead is my best one! thanks.
>
> "Gustavo E.E. Grin\ufffdvero" <geegrinovero@...> wrote:                               Hi all,
>  If anyone is willing to assembly an expression pedal, I could try to make a diagram of my original.
>  I don't know how hard is to modify an standard expression unit to make it compatible with the CS80.
>  As far as I remember, it uses lamp(s) and photo cell(s)...
>  Let me know.
>  Gustavo.
>  
>  ----- Original Message ----- 
>    From: rj krohn 
>    To: yamahacs80@yahoogroups.com 
>    Sent: Thursday, December 20, 2007 12:55 PM
>    Subject: Re: [yamahacs80] CS80 Leg Bracket Hardware & Expression pedal?
>  
>  
>  anyone have any details on CS80 Expression Pedal - subs or other
>    models which used it?
>  
>