[sdiy] Modular synth input/output protection.

[Tim Parkhurst]

One nice thing about ±5V signals: you can use standard analog switches
(4016, 4066). One could even make a point for ±2.5V signals, which
would allow you to use a lot of those nifty digital pots out there.
And of course, the Minimoog runs its rails at ±10V, so I would think
it's signal levels are around ±5 to 7V, correct?

Tim (fan of whatever works) Servo
--
"Imagination is more important than knowledge." - Albert Einstein

****************
On 1/22/06, Dave Kendall <davekendall at ntlworld.com> wrote:
> Hi.
>
> Any fans of ±10V out there? or would it be wise to scale everything down to
> ±5V?
> I notice some CGS modules can handle ±10V.....
> Just wondering...
>
> Dave
> >
> > Here's an excerpt from Thomas Henry's Drum Cookbook. This section
> > talks about synth standards and is itself from Bernie Hutchin's
> > Electronotes:
> >
> > *************************************************
> > CONTROL INPUTS
> > ·Voltage:           0 to +5V
> > ·Impedance:     100K Ohm
> > ·Overvoltage and reverse voltage protected
> >
> > AUDIO INPUTS
> > ·Voltage:           ±5V
> > ·Impedance:     100K Ohm
> > ·100k attenuators on the inputs
> > ·DC coupled where possible
> >
> > AUDIO OUTPUTS
> > ·Voltage:           ±5V
> > ·Impedance:     1K Ohm
> > ·DC coupled where possible
> > ·Short circuit protected
> > ******************************************
> >
> > From what I can see, the protections listed above are taken care of by
> > standard buffers on inputs and outputs, including 100k resistors on
> > inputs going into an op amp buffer, and 1k resistors on outputs
> > (usually coming from an op amp buffer). One place to watch out might
> > be digital I/O. This is where I would probably use a resistor, zener,
> > or schotky diodes to ground and +V (the digital supply).
> >
> > Tim (enjoying a lazy Sunday morning) Servo
> > --
> > "Imagination is more important than knowledge." - Albert Einstein
> >
>
>
>