[sdiy] center tapped pots?

[peter edwards]

Thanks tom... thats a pretty cool circuit... but isn't this more of a  
cross fader? I'm trying to figure out how to take two parallel audio  
signals (split from one input, processed then mixed to one output)  
and feed the output of one into the input of another. Think of it  
like this, you've got a distortion pedal and a flanger pedal. Your  
guitar signal is split into two identical signals which are fed into  
the two effects. The two effected outputs are then mixed together so  
you have a distorted signal and a flanged signal in parallel. What if  
you want to send some of the fanged signal into the distortion or  
visa versa? If the dist. was looped into the flange and the flange  
was looped into the dist. you would just get feedback, so they need  
to be adjusted at the same time to ensure that only one is looped at  
a time. So I figure I need a dual pot. It needs to be center tapped  
so that the complete volume curve for each loop only takes up one  
half of the full rotation. That way the volume curves for the two  
loops never overlap.....


On Apr 8, 2007, at 7:51 PM, Tom Wiltshire wrote:

>
> On 8 Apr 2007, at 02:32, peter edwards wrote:
>
>> Howdy y'all...
>> I'm looking for a couple 100K, dual, center tapped pots and can't  
>> seem to find them anywhere. I found some manufacturers but no  
>> small quantity distributors. Anybody have any leads?
>>
>> Maybe there's an alternate method for achieving my goal and I  
>> don't need a center tapped pot, but I can't think of one...
>
> You could try this arrangement, which allows you to do the same  
> thing with a standard single pot:
> <MIxer.gif>
>
> When the pot VR3 is at 'max', you're feeding in Input 1 and an  
> inverted version of Input 2, which cancels the Input 2 signal going  
> in the other input - thus you only get Input 1. At the other  
> extreme, you obviously just get Input 2. Half way between, you get  
> a half-cancelled Input 2 (so at half-volume) and a half-volume  
> Input 1.
>
> It uses a few op-amps, but it can be handy.
>
> Regards,
> Tom
>
>
>
>