vca: no CEM, no SSM (was: ssm-2040)

[Sean Costello]

> At 01:36 PM 11/08/98 -0400, Andrew Schrock  wrote:
> >I know this has been tossed around before, but has anybody come up with a
> >good non-CEM, non-SSM VCA solution?

Well, I don't know if this is a good solution, but it might be an
interesting one: Nyle Steiner describes a circuit in "Voltage-Controlled
Amplifier Covers 70dB Range" in EDN (March 5, 1975, p.72).  Apparently
the circuit uses 5 transistors and a series string of 8 diodes. 
According to Bernie Hutchin's description of the article, "Carefully
matched components are not required."  

I was going to go to UW to photocopy the article today after work, but I
ended up staying at home and making a loop of "Sister Ray" by the Velvet
Underground on my little SP-202 sampler.  Not terribly conducive to
sanity.

Steiner also has an article in the December 6, 1974 issue of Electronic
Design, describing a voltage controlled low pass/high pass/bandpass
filter.  I only know 3 things about it:

1) It uses diodes as the CV elements;
2) It is NOT a state-variable design; and
3) The University of Washington doesn't have that issue of Electronic
Design.

So, any kind souls out there have access to a good university library, a
photocopier, and a scanner? 

Later,

Sean Costello