[sdiy] linearize OTA for VCF?

[Terry Michaels]

Message text written by "Ian Fritz"
>> The way I got around this in my VCA design, which uses the CA3280 with
> diode bias activated, is I set the gain levels so that the OTA clipping
> point coincides with the output buffer reaching the power supply rail.
> You're going to clip there anyway.

That's a good tip, thanks. Of course, the buffer gain can be whatever you
want, since it is an I-V converter. What value of gain (or diode bias
current) do you use?

  Ian<

Hi Ian:

The diode bias pin has a 68K resistor to +15 volts, the output of the
CA3280 drives the inverting input of an opamp, the opamp has a feedback
resistor of about 30K.  Iabc has a maximum of about 0.5 mA.

Terry Michaels