[sdiy] 1 Meg input level pots?

[keith sterling]

My experience when I used 1Meg pots on audio and cv inputs was that  
they became more susceptible to noise and hum, especially when the  
pot is set near minimum (high resistance).  I had to go back and  
replace the wiring after the pot with shielded cable which helped a lot.

Keith



On May 19, 2007, at 1:47 AM, Seb Francis wrote:

> I would say that they are most suitable for audio input use.  If  
> you have a 1M linear pot going to a 100K resistor into a summing  
> (inverting) opamp configuration then you will get almost exactly an  
> ideal log pot response.  I don't think thermal noise will be a  
> problem with 1M into 100K into a FET type (e.g. TL07x) opamp.
>
> You can see the response for yourself here:
> http://www.mindspring.com/~clist/PotGraph.html
> (also see the lower schematic on this page)
>
> Seb
>
>
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