Tone Pots: Linear or Audio? Why?

[MarshallPlexi]

What about for a mixer circuit that blends two preamps? Obviously a ganged linear would be correct since the pots would meet in the middle at 50% rotation, but I'm not sure how the ear would perceive that. Thoughts?

[David Schwab]

Dual ganged blend pots with center detents commonly used on basses to blend pickups often use M/N taper pots. It's kind of a log/anti log taper, but it's a bit more concentrated around the detent. EMG uses linear taper for their blend pots, and they work fine as well.

Also for passive instruments, the taper can help with the loading you get when you turn the volume down. It's less noticeable with active instruments, which have a more even drop when you turn the volume down.

Stereo balance controls are linear taper. Audio taper is needed when you are going to be changing the volume, like a fader on a mixer, and you want it to be smooth from quiet to loud.. or at least seem smooth.

[Mark Hammer]

I still maintain that optimal taper for a tone pot will depend on how you intend to use it.

If, for example, you like to do pinky wah, then a log taper will let you cover a lot of ground quickly. If you use other cap values that would make it helpful to be able to cover a lot of ground quickly, simply because of the way in which you adjust tone, then log can be useful.

Myself, I've taken to using a bidirectional tone pot in which I have a different tone cap at each extreme of the control's rotation, to produce two different rolloffs, and the mid-point is no rolloff. Obviously, in such an instance, the pot must be linear or else how would I ever know where the no-cut position is?

If a person simply doesn't HAVE any particular agenda for their tone control, and is using stadard cap values, then linear is tried and true.

Incidentally, there ARE other tapers besides lin and log, and you can create your own need-specific taper by means of paralleled resistors. Read this and find out how: http://www.geofex.com/Article_Folder...s/potscret.htm

[MarshallPlexi]

Stereo balance controls are linear taper. Audio taper is needed when you are going to be changing the volume, like a fader on a mixer, and you want it to be smooth from quiet to loud.. or at least seem smooth.

So for a situation like blending two preamps into one signal, it would be best to use a Linear pot?

[billyz]

I prefer Audio Taper for both Volume and Tone on Guitar. But the quality of the taper is very important. I had a nice Fender Nocaster , but was never happy with the feel of the Controls. I tried many different makes of pots, it was not until I bit the bullet and put in the Allesandro pots That it finally felt right.

I also build amplifiers and most amp designs use Audio Taper for both Volume and Tone . The exception being the Middle control. I suspect it has something to do with The Fletcher Munson curves, Where the bass and treble frequencies are most skewed and the Middle frequencies are less affected by volume shifts.

I find a good 10% audio taper to be about right, where the pot is at 50% rotation the first half is gaining 10 % value.

[David Schwab]

So for a situation like blending two preamps into one signal, it would be best to use a Linear pot?

Yes, because you want half way to be half way.

[MarshallPlexi]

Sweet! I'll see how that works.

[black_labb]

What David said, is what I always felt was right.


The ear hears volume in a logarithmic fashion, so you would use a log pot for volume.
I still could not understand why anybody would use anything but a linear pot for tone. The logarithmic compression that your ear hears in, is only for volume, not tone/frequency differentiation. The frequency response of your is not flat, but it isn't logarithmic. Your ear is most sensative from 1kHz to 4kHz. below 1kHz it starts to drop. It's a slope, but I still would consider this drop as linear

the ear doesnt hear frequency in a log fashion, but the tone pot is actually a volume pot that effects the higher frequencies. it doesnt pan between frequencies, it just cuts a certain band an amount determined by the pot. if you want a smooth travel like a log pot used for volume, use a log pot. both types of pots have all the same values on them, so its not a big deal.

[David Schwab]

I want to add that there is no right and wrong, just what you prefer. Either taper will function correctly, but you might like the feel better with one or the other. So it can't hurt to try one, and if you don't like the way works, try the other taper.

[voodoochild]

For guitars audio log taper for both volume and tone. Tried linear - didn't care for the tapers.



Cheers,

I couldn't agree more. In fact I replace those stock 300k linear pots in Gibsons all the time because people complain about the taper. I put a 500k audio in place of it and they are always happy. Linear taper looks good on paper but sounds bad to the human ear. The linear taper isn't manageable at all in passive guitar circuits IMO.

[tubeswell]

For my tuppence worth (since this thread has been resurrected), I understand that audio vs linear tapers work differently in different tone stack applications.

Take a 5E3 tone control for example, the 1M Tone pot is in between a 500pF cap and a 5nF cap, and as the wiper goes down to the 5nF end, more frequencies altogether are passed to ground (making it more bassy) and as it goes to the 500pF end, more high frequencies are bypassed to the next stage (making it more trebly). So in that application the pot is more like a mixer/balance pot and a linear taper would work fine (but so does an audio taper).

But where you have a simpler tone control, like a pot wired as variable resistor in parallel with smallish cap, it may be better for the pot to be audio taper to 'hear' the difference between hi and lo more evenly.

[tedmich]

I agree with David as well, but mainly because its MUCH easier to find very high quality linear pots for cheap, like these:



which are beautiful 2 watt cermet dual 5Meg pots made by Bourns which can be made into any lower value with a parallel resistor and separated into a trim pot and single pot quite easily...or used as a 10Meg guitar volume pot....

AND cost $2 at www.goldmine-elec-products.com
(no affiliation, I just bought all I needed)

[David Schwab]

AND cost $2 at www.goldmine-elec-products.com
(no affiliation, I just bought all I needed)

Hey, cool! Thanks for the link!

[Steve A.]

My two cents worth on this discussion...

I have been replacing the audio volume pots on most of my guitars with linear pots for a specific reason: if you need to turn down your volume when it is set to 10 you have much more control with a linear pot. This is very important to me if I am constantly adjusting the on-board guitar volume control all night, from song to song and during the songs themselves. I was using my Tele B-Bender last weekend and I hadn't already replaced the audio taper volume control- it was a real b*tch keeping the volume at the levels I wanted.

So my rule of thumb is this: if you are mainly concerned with turning down the volume from 10, then a linear taper works better. If you are mainly concerned with turning the volume up from 0- like doing swells- then an audio taper is better. (As is the case for all thumb rules, there are plenty of exceptions!)

Of course someone might just use a volume pedal and leave their on-board volume pot(s) set to 10 but that ain't me...

Steve Ahola

[tedmich]

I've seen recommendations for both linear and audio taper guitar tone pots. Which works best? Why?

someone has probably mentioned this, but when using a linear pot as a variable resistor (wiper tied to one leg) you can add a parallel resistor and make a pretty good approximation of a log/audio taper. You can't do this for a pot used as a voltage divider, google "secret life of pots" or see Rod Elliott's site