[sdiy] Unrolling the OBX voice card

[Steve Lenham]

----- Original Message ----- 

From: "Oakley Sound" <tonyallgood at btinternet.com>
> > Yes, the attack, decay and release voltages are 0 to -5V (MINUS 5V)
> and the sustain voltages are 0 to +5V (PLUS 5V).
>
> No. The OB-X, and the OBXa too, feeds the CEM3310 directly. They need to 
> be low negative voltages to set the time constants. 0 to -240mV maximum.
>
> See the CEM3310 datasheet for more details.
>
> -5V into one of the CV inputs would probably kill the 3310.
>
> Tony

You are right of course, Tony. Apologies for my mistake - I checked the 
CEM3310 data before posting but didn't register the resistive attenuator 
required to give the 5V span.  The OBX implements that attenuation in the 
inverting amps following the CV demultiplexer.

Cheers,

Steve L.