[sdiy] best floating voltage-controlled resistor implementation?

[harry bissell]

Dino Leone wrote:
> Q
> Tim,
> Sorry I wasn't precise. I was thinking about digital potentiometer. I was
> looking at the MCP42100 (dual 100kOhm, 256 steps). The question is would
> the signals be too high to pass through it? I would guess the max.
> amplitude would be +/-5V so I should be OK when driving the 42100 with +5V.
> Right?
>   
moot point... in most OTA designs... the signal will be attenuated to no 
more than 50mV
or horrible distortion (or, BBD heads... ~groovy~ distortion :^) will 
result.

You could easily scale your signal to fit the pot. There ARE some that 
have +/-15V range
(Analog Devices).

The comment about 'zipper noise' is valid. You COULD easily make the pot 
wiper step with
voltage. And there is a circuit in EDN this week that claims to avoid 
zipper noise.

fvck that. I don't think it will work. It will REDUCE zipper noise as 
promised nut I think at the
end of the morning, you will find that Santa did not leave the pony you 
wanted under that tree...

H^) harry