[sdiy] linearize OTA for VCF?

[Scott Gravenhorst]

Hmm.  A test jig where you can run a nice linear ramp
thru an OTA while allowing a current control for the
diode bias.  Look at the output on an oscope while 
knob twisting.  This could give some nice data perhaps
to decide what diode currents vs what input amplitudes
vs what kind or how much distortion you get/want.
Probably need a knob for Iabc too.

"Ian Fritz" <ijfritz at earthlink.net> wrote:
>Hi Harry --
>
>> It seems to be a trade of lower noise within the linear range... and then
>> horrible
>> clipping... (with diode bias)
>>
>> or higher noise and soft clipping.... (without)
>
>Yes, that would seem to be the case.
>
>> I don't know which I'd choose.
>
>Well, that's the question, really. People have looked at this tradeoff for
>VCA's and seem to have strong opinions about the results. People also seem
>to have strong opinions about the importance of distortion in the Moog
>ladder filter. But hasn't anyone looked at the OTA-based filter case?
>
>  Ian
>

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