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Re: I Need to Fashion a Reverse Log Pot

12/14/2000 6:27 PM
Stephen Conner
Re: I Need to Fashion a Reverse Log Pot
Unfortunately (no matter what RG says) you can't make the reverse log taper for a 2-connection setup using an external tapering resistor. It only works for the 3-connection setup.  
What you need to do is get your hands on one of the mini Alpha dual gang pots. The resistive element fitted to the back (the opposite side to the shaft) is easy to remove. And, crucially, because it's fitted the opposite way round, the wiper runs backwards on it. So, Alpha use a reverse log element in this position, which gives a normal log taper.  
So, if you prise it off and replace it with a normal log element (which you get by dismantling a regular 1-gang 1M log Alpha pot) voila... a reverse log taper. (Just leave the front section unconnected)  
if that makes sense  
Steve C.
And now, a word from our sponsors:

12/14/2000 8:49 PM
Steve A.

    Do you have a stock number to order the mini Alpha dual gang pots?  
Steve Ahola
12/15/2000 11:29 AM
Paul D.

Thanks for your reply - I did the calculations according to my understanding of RG's instructions & I couldn't see how it could work. I'm in Australia - I'll have to search for a supplier of Alpha pots. Where are they made?  
Paul D.

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