[sdiy] Filters

[jbv]

harry,

> OTA might be more 'high tech' but also a lot harder to control. There is time
> delay through the OTA (not much but in a feedback loop it could be enough
> to notice)... OTA has limited signal handling capacity, high offset voltage
> etc...
>
> Where the LED/Photocell might work just fine, and for maybe $.50 (usa)
>

Do you mean that a LED/Photocell could respond efficiently
to very fast envelope signals with different shapes (linear, log,
dome...) ?
This is not the experience I had with photocells which had a
certain latency... but that was back in the late 70's... Perhaps
did technology improve since...
If that solution could work, that would be great, in terms of
cost, design time and PCB room...

Best,
JB