[sdiy] Discrete OTA

[Andrew Simper]

On 5 April 2014 12:26, David G Dixon <dixon at mail.ubc.ca> wrote:
>> Incorporating the expo converter is handy, but the Osamu
>> Hoshuyama temperature compensation is a fairly compelling
>> argument for the 2164.
>
> Yes it is.  That scheme is in every VCO I've ever designed, including the
> Dixie, and Rubicon, and the Atlantis.
>
>> To play devils advocate, I believe the SEM3320 used
>> conventional OTA's and made for a compact design, and no-one
>> complains about the sound of an OBX-a!
>
> Yeah, actually, my first 24dB cascaded-stage filter sounded really nice with
> OTAs.  It just is so much easier to use 2164.

Can the 2164 be used as an expo + linear voltage to current converter?
I was thinking along the lines of feeding a linear hz control voltage
into the input pin of a 2164 stage, and then the expo control voltage
into to the control pin of the 2164, and then take the output current
as control current for an OTA.

---Andy