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Old 29th October 2012, 09:04 PM   #1
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Default line level stereo volume control using one pot?

Any schematics how this is typically done with the least distortion?
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Old 29th October 2012, 09:16 PM   #2
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Are you looking for something like this?
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Old 29th October 2012, 09:20 PM   #3
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Quote:
Originally Posted by lanchile View Post
Are you looking for something like this?
I was looking for a solution that used one pot. Such as a pot with a single output.
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Old 29th October 2012, 09:26 PM   #4
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How do you expect to run a stereo signal through a single wire? What's wrong with using a dual pot like shown above?
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Old 29th October 2012, 09:34 PM   #5
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Quote:
Originally Posted by Fusion916 View Post
I was looking for a solution that used one pot. Such as a pot with a single output.
That is one pot! But if you want to get a single output...that will be MONO not stereo!!!
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Old 29th October 2012, 09:44 PM   #6
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I was looking for some kind of IC or transistor solution. Like a voltage controlled variable resistor type of thing.
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Old 29th October 2012, 09:54 PM   #7
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Do you want a voltage regulator?... is it to adjust audio output?
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Old 29th October 2012, 10:41 PM   #8
basite is offline basite  Belgium
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VCA's.

use one single pot that controls a DC voltage, which controls a VCA IC, such as the THAT 2180.

http://www.thatcorp.com/datashts/THA..._Datasheet.pdf

advantage here is that you can control "infinite" amount of channels with one pot, downside is that it will require some circuitery.
but, it's an option I am building a monitor controller now, with those VCA's, and so far, everything works out well...
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Old 29th October 2012, 10:47 PM   #9
wa2ise is offline wa2ise  United States
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I did it with a vacuum tube, see the thread over in AudioKarma Electronic volume control with a 6HS8 "TV" tube - AudioKarma.org Home Audio Stereo Discussion Forums
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Old 30th October 2012, 01:00 PM   #10
Mooly is online now Mooly  United Kingdom
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Quote:
Originally Posted by Fusion916 View Post
I was looking for some kind of IC or transistor solution. Like a voltage controlled variable resistor type of thing.
It can be done with 3 single opamps and a single pot

I came across this idea many years ago and credit for this goes to Brian Gough of Xicor. I thought I would throw the basic configuration into LTspice and sure enough it does work...

Its really a variation of the Baxandall active volume control. The wiper of the pot is grounded and the "two ends" control the gain stages. How successful it might be in practice is hard to say. The wiper of the pot must have near perfect contact on the track to ensure perfect channel separation.

It was a very clever idea non the less although one I have never seen implemented. I guess the digital revolution made such processing in the analogue domain redundant.


R5 and R5A are the single pot. If the pot is 1K then if one resistor is 900 ohm the other is 100 ohm and so on.
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