audio-tapered pots

[Eight_Stringer]

Hard to convince some people of the reason the log potentiometer was invented in the first place. Just use a linear "pot" in place of a log pot and you will soon find out why they invented the log pot. Since pots cost around $2 it is easy to do the experiment yourself.
Regards.

 

[Stempelloos]

I don't think you really understand the difference...
In plain english: Audio taper pots give you a smoother response than linear for volume controls, as volume works in a logarithmic fashion. Tone controls on the other hand, which don't handle any audio (a tone control is a simple low-pass filter) work best with linear taper pots.

Tone control does work with a logarithmic pot, it's response is not as direct as a linear pot but they do react. I've installed a CTS logarithmic pot for tone together with a linear volume pot to a humbucker. There's a noticeable difference between the knob turned at 10 and 1. It's kinda mellow and subtle compared with a linear tone pot,
but it works.

 

[line6man]

Tone control does work with a logarithmic pot, it's response is not as direct as a linear pot but they do react. I've installed a CTS logarithmic pot for tone together with a linear volume pot to a humbucker. There's a noticeable difference between the knob turned at 10 and 1. It's kinda mellow and suble compared with a linear tone pot,
but it works.

I didn't say that log taper pots wouldn't work, i said that linear taper pots work better.

 

[Stempelloos]

I didn't say that log taper pots wouldn't work, i said that linear taper pots work better.

You're right, i got you wrong.

 

[walterw]

Interesting. These terms must be opposite for instrument pots versus the way they are defined in the amplification world. I could be wrong, but the way you describe linear tapers is the opposite of how they should perform.

no, the terms are the same. the pot in question just behaves differently depending on the circuit it's in.

I'm just posting this again to make sure I have that right. On an amplifier, a log/audio taper on the master volume allows for a smooth, even sounding increase in volume through a much larger percentage of the pot's travel than a linear taper, which 'jumps' much earlier.

correct, and the fender blues deluxe amp is a perfect example; they come with linear master volumes, which in that distortion channel jump up really fast from "0", making it seem in the music store like the amp has huge volume reserves. ("wow, i can't even turn it up past '3' and it's loud as hell!") converting that master to an audio taper is a common mod for those amps.

on a passive bass guitar into a clean bass rig, however, linear volumes will have an even sweep from "0" to "10", while audio tapers will jump at "8" or "9".

there seems to be some resistance (get it?) to the idea, but i note that not one post on any thread i've seen about it has been from someone who actually tried linear volumes in their passive bass and didn't like it.

i have seen lots of complaints from players whose bass volumes dropped off real fast from "10", which is what audio taper pots do!

 

[JustDavid]

There seem some knowledgeable folk into this thread, so I'll ask for help on a topic that's long boggled me. Gonna try some statements & hopefully get "shot down" in the right direction

1/ Active volume controls give consistent results with audio or log taper pots while passive volume controls give consistent results with linear taper, 'consistent' meaning that the difference between 1 & 2 is similar to 9 & 10's.

2/ First-order tone controls (i.e. one capacitor or inductor) give consistent (1 to 2 = 9 to 10) results with log taper pots because perceptions of frequency are a logarithmic function.

3/ Given the above are "proper" pot choices, you can customize your controls to better fit your style of adjustment. For example (& possibly wrong; pulling it out of a hat that sits on a boggled mind) you could use a log pot wrongly on a tone control to get finer adjustment in the brighter section of the control, at the expense of coarser adjustment in the darker section.

How wrong am I?

 

[walterw]

There seem some knowledgeable folk into this thread, so I'll ask for help on a topic that's long boggled me. Gonna try some statements & hopefully get "shot down" in the right direction

1/ Active volume controls give consistent results with audio or log taper pots while passive volume controls give consistent results with linear taper, 'consistent' meaning that the difference between 1 & 2 is similar to 9 & 10's.

2/ First-order tone controls (i.e. one capacitor or inductor) give consistent (1 to 2 = 9 to 10) results with log taper pots because perceptions of frequency are a logarithmic function.

3/ Given the above are "proper" pot choices, you can customize your controls to better fit your style of adjustment. For example (& possibly wrong; pulling it out of a hat that sits on a boggled mind) you could use a log pot wrongly on a tone control to get finer adjustment in the brighter section of the control, at the expense of coarser adjustment in the darker section.

How wrong am I?

i think your statements are dead on, and nicely stated, especially the comment about active vs. passive volumes. i noticed recently on a fender marcus miller jazz bass (switchable preamp) that the stock 250k audio volumes had the expected abrupt drop from "10" to "8" in passive mode, but switching in the preamp made them seem more even.

your example is backwards, though. a linear tone pot will have little change over the "bright" end of its travel, and an abrupt change at the "dark" end. in normal use, it will seem like it does nothing until it's almost all the way off.

 

[Stempelloos]

I've had a look around in local webshops to find out how they advertise
their potentiometers:

"Volume can be done with lineair and log/audio
Lineair is best for tone

Another shop:

500/250 K audio tonepotentiometer
500/250 K lineair volumepotentiometer

Another shop:

DiMarzio Tone potmeter

Audio-tapered (logaritmic) Di Marzio Tone Potmeter
resistance: 1 MΩ"

One sells lineair as the best for for tone, another sells log/audio as
tone pot.

 

[KJung]

no, the terms are the same. the pot in question just behaves differently depending on the circuit it's in.


correct, and the fender blues deluxe amp is a perfect example; they come with linear master volumes, which in that distortion channel jump up really fast from "0", making it seem in the music store like the amp has huge volume reserves. ("wow, i can't even turn it up past '3' and it's loud as hell!") converting that master to an audio taper is a common mod for those amps.

on a passive bass guitar into a clean bass rig, however, linear volumes will have an even sweep from "0" to "10", while audio tapers will jump at "8" or "9".

there seems to be some resistance (get it?) to the idea, but i note that not one post on any thread i've seen about it has been from someone who actually tried linear volumes in their passive bass and didn't like it.

i have seen lots of complaints from players whose bass volumes dropped off real fast from "10", which is what audio taper pots do!

Interesting. It makes sense that different circuits would interact in different ways. Thanks.

 

[JustDavid]

i think your statements are dead on, and nicely stated, especially the comment about active vs. passive volumes. i noticed recently on a fender marcus miller jazz bass (switchable preamp) that the stock 250k audio volumes had the expected abrupt drop from "10" to "8" in passive mode, but switching in the preamp made them seem more even.

your example is backwards, though. a linear tone pot will have little change over the "bright" end of its travel, and an abrupt change at the "dark" end. in normal use, it will seem like it does nothing until it's almost all the way off.

Hey, thanks Walter!!

There's lots of info on the Internet, but it can be hard to sort out what's actual.

 

[ModulusMK]

Post #7 from line6man is right and correct. The pots are just used by the application requirements. Sometimes you need to use Audio taper (or log pot) some times Linear. Basically audio circuits are controlled by Audio tapers, but there are exceptions. In guitars mainly both work fine. Try both of them and you'll hear what is the difference.

 

[Angus]

Basically audio circuits are controlled by Audio tapers, but there are exceptions.

No, the name "audio taper" has nothing to do with being meant to be used in "audio circuits"- it's just called audio taper because it's given a logarithmic tapering to conform closer what our ears actually perceive (basically, it's set to a scale that more closely conforms to a dB scale). It doesn't mean that it should necessarily be used in audio circuits. In fact, you generally do not want them in any sort of control signal application, and only in certain instances are they helpful in audio-rate applications. You may already know this, but I can't tell you how often I hear the misconception of what the "audio" part of "audio taper" refers to.

 

[ModulusMK]

No, the name "audio taper" has nothing to do with being meant to be used in "audio circuits"- it's just called audio taper because it's given a logarithmic tapering to conform closer what our ears actually perceive (basically, it's set to a scale that more closely conforms to a dB scale).

Yes, but I didn't meant that as a must for audio circuits, only that most of the logarithmic changes are required in them. Hardly you'll find log pot in a digital circuit or something else (I'm not saying you wont, just it's very rare).
That is why I mentioned audio circuits. Although there are Linears in audio circuits too. Don't take me for granted