# Can I substitute a mono potentiometer for a stereo one?

I have a PCB for a headphone amp that has a 6-hole pad for a single potentiometer. I've only got 3-pin ones in my box o' parts. Can I substitute the mono pot for the stereo pot, tie the sets of pads together with jumpers, and achieve the same results? Or should I order the right part?

Based on how I'm visualizing it (below), it seems like I should be able to. Am I missing anything conceptually? or is this a good solution.

  1   2   3
+-------+---+
| O   O | O |      Jumpers between 1-4, 2-5, 3-6
+-----------+
| O   O | O |    <--  Mono Pot here
+-----------+
4   5   6

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Based on how I'm visualizing it (below), it seems like I should be able to. Am I missing anything conceptually?

Perhaps you're visualizing that the pots merely affect the control voltages fed to voltage controlled attenuators, one for each channel.

However, it is most likely that the pots actually form two separate voltage dividers feed by the analog signals for each channel.

If you combine the L and R signals in a single pot, you will no longer have separate L and R signals; each channel will carry a L + R signal.

As Kaz points out, it is also possible that you might damage the stages feeding the volume control.

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You'll turn it into a mono amplifier by doing that. I doubt that comes within your definition of 'the same results'.

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I'm missing something here...wouldn't I just turn up each channel the same amount? L/R comes in, L/R comes out? Or would ganging the sets of pads MIX my signal into a single mono output? – dwwilson66 Dec 15 '12 at 0:51
Not only would it mix, but something could be damaged. One of your jumpers could be tying together two amplifier output stage that drive different voltages. – Kaz Dec 15 '12 at 0:56
OK...that makes sense. I'll read those chapters on audio a little more closely. Thanks for the add'l info. – dwwilson66 Dec 15 '12 at 4:24

Your box o' parts has two or more single potentiometers. You can use two pots. Then you have separate left and right volume controls. Or go to an electronics store and spend the dollar or two to get a dual-ganged pot. It is two potentiometers driven by one shaft.

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Unfortunately, the case I have to stick this back into only has one hole to pop a pot through... :( ...and of course, NONE of my local electronic stores have ganged pots. Looks like a trip to mouser.com is in order, and I can't get the project done this weekend. Damn this being patient crap. ;) – dwwilson66 Dec 15 '12 at 4:26