Proper way to make balance potentiometer for audio

Sangram

Moderator
Paid Member
2002-09-25 11:01 am
India
The ideal way? Buffer the volume control signal and use a dedicated half-and-half balance control, or make your own by using half the steps of a ladder attenuator.

Otherwise the hacked single pot with two series resistors works well enough for 99% of users. Buffering is critical for good response of passive attenuators.
 

rayma

Member
2011-04-29 8:37 pm
Thanks Rayma how do you calculate the 30K resistors? The 100K pot is lin or log? It's OK always 100K pot or depends the value of volume pot? Where to install: I guess before the volume pot right?

Just before the volume control. This circuit is for a linear balance pot.
Post your schematic and this will be easier, since the values depend on your circuit.
 
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Mark Johnson

Member
Paid Member
2011-05-27 3:27 pm
Silicon Valley
Why not copy the idea Nelson Pass used in his "Threshold NS10" design: use two potentiometers for balance and one more for volume? See image below.


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Mark Johnson

Member
Paid Member
2011-05-27 3:27 pm
Silicon Valley
The First Watt B1 with Korg Triode includes two separate, single-gang potentiometers for gain adjustment. One pot for the Left channel and another pot for the Right. Link to review including photos.

A diyaudio member inquired, "When you have dual mono pots without any clicks to ensure same setting of both pots, then you have to do the "tracking" by "eye and/or ear"?"

And Nelson Pass answered, "I would have thought, but I find that separately dialing them up makes you more aware of the balance. It doesn't bother me at all. Perhaps Mark Levinson's preamp had something....."

(Here is a link to his post.)

I've attached an image of the Mark Levinson preamp which I (MJ) think Nelson Pass is talking about. It has two balance pots and a volume pot.

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Mark Johnson

Member
Paid Member
2011-05-27 3:27 pm
Silicon Valley
Have a look at Douglas Self's book "Small Signal Audio Design". The 2nd edition has two full chapters about this (ch. 13 & 14), with large numbers of tables, graphs, formulae, and discussion. The publisher's website (Focal Press) has the book's Table Of Contents online and viewable; I took a screen capture image of one page, attached below.

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