[sdiy] high quality expo VCA

[Seb Francis]

Hi Charlie,

The book is "The Art of Electronics" by Horowitz and Hill (second edition) ISBN 0-521-37095-7.

It's quite expensive, but I highly recommend it as a technical (but not *too* mathematical) electronics reference, with plenty of useful stuff for the home synth builder :)

The circuit I mention is on page 212, and is explained on page 213 onwards.

Seb


charlie lamm wrote:

> I would like to see this...for something I am building as well....do you
> have the book title?  Maybe the University library has it.  Thanks in
> advance....
>
> On Fri, 22 Nov 2002, Seb Francis wrote:
>
> > Fernando de Izuzquiza wrote:
> >
> > > But still looking for a good VCA with expo/lin switchable response...
> >
> > > Has anyone designed an expo circuit with the SSM2164? We have Mike Irwin LIN design, and the chip is
> > > originally expo so... it would be nice to switch between the two responses.
> >
> > You could switch in and out a logarithmic amplifier between the CV and the VCA, I think that should allow expo/lin response with a SSM2018/2164/etc.
> >
> > I've got a circuit in a book which uses a matched NPN-pair, 2 opamps, 4 resistors, a cap and a diode to do this.  I can describe the circuit in more detail if you want.  I believe you can also get single chips which do this.
> >
> > Seb
> >
> >