What would I expect from a linear taper volume pot?

iPie · #1 06-05-2011, 01:32 PM

Just taken my bass apart to have a look see if I can do any upgrading. I've decided to do some shielding, cut down the amount of wire (theres meters of it in there needlessly!) and I'm thinking of replacing my pots as they make scratchy noises through my amp.

One interesting thing is that the volume pot (Also a push pull) seems to be linear taper (says B500K) on the side, and I was under the impression that it should be audio taper (A?).

My bass is active and has a preamp, so is the linear taper okay or should it definately be audio taper?
I have noticed that the pot seems to do most of the volume changing within the top 3 or 4 degrees of turning??

Sorry for the long and incoherent post :S

Thanks

**line6man** · #2 06-05-2011, 01:38 PM

You're going to get people fighting to the death for both sides.
It's pretty much personal preference.

IMO/IME, linear taper pots work better for volumes. They give you a nice smooth sweep from 10 to 0, without the big jump you get with audio tapers from 10 to 8-ish.

iPie · #3 06-05-2011, 01:40 PM

Quote:

Originally Posted by line6man

You're going to get people fighting to the death for both sides.
It's pretty much personal preference.

IMO/IME, linear taper pots work better for volumes. They give you a nice smooth sweep from 10 to 0, without the big jump you get with audio tapers from 10 to 8-ish.

are you sure its not the other way around??

That's exactly what I've been observing from my volume pot and i THINK it is linear taper?

Most places seem to say to use audio taper for volumes?

**line6man** · #4 06-05-2011, 01:42 PM

Quote:

Originally Posted by iPie

I have noticed that the pot seems to do most of the volume changing within the top 3 or 4 degrees of turning??

That doesn't make sense. Remember that a linear taper rolls off slower than an audio taper.

With a linear taper, the 50% point in the resistance range occurs at one half of the rotation. On an audio taper, it occurs at around 4/5 of the rotation. This means you have to roll a linear taper down to "5" to get the same effect as an audio taper on "8."

iPie · #5 06-05-2011, 01:45 PM

extremely confused

I thought the whole point of audio taper was for use in volume pots, because the way we percieve sound is not linear, so the halfway point in a linear taper will not sound like half the volume to us?

I have noticed most of the volume change between 8 and 10 and I'm almost certain what i have is a linear taper

**line6man** · #6 06-05-2011, 01:47 PM

Quote:

Originally Posted by iPie

are you sure its not the other way around??

That's exactly what I've been observing from my volume pot and i THINK it is linear taper?

Most places seem to say to use audio taper for volumes?

I'm sure.

Like I said, you're going to get people on both sides, however.

I noticed that you are in the UK. I've heard that European pots are labelled such that A denotes a linear, B denotes a log and C denotes a reverse log. Have you tested the pot with an Ohm meter?

**line6man** · #7 06-05-2011, 01:49 PM

Quote:

Originally Posted by iPie

I have noticed most of the volume change between 8 and 10 and I'm almost certain what i have is a linear taper

That is a classic audio taper.

iPie · #8 06-05-2011, 01:50 PM

Quote:

Originally Posted by line6man

I'm sure.

Like I said, you're going to get people on both sides, however.

I noticed that you are in the UK. I've heard that European pots are labelled such that A denotes a linear, B denotes a log and C denotes a reverse log. Have you tested the pot with an Ohm meter?

I'm afraid I dont have an Ohm meter or anything like that so no way of measuring it

I may take it into my local shop at some point for some advice

**line6man** · #9 06-05-2011, 01:53 PM

Quote:

Originally Posted by iPie

I'm afraid I dont have an Ohm meter or anything like that so no way of measuring it

I may take it into my local shop at some point for some advice

You should be able to pick one up for very cheap.
I've seen multimeters as cheap as $4 at hardware stores.

iPie · #10 06-05-2011, 01:59 PM

I think I may do that, I never get round to those kind of things

I still need to buy some solder which I have run out of lol.

If audio taper aren't used for volume pots, can I ask what the point of them is? because it doesn't seem like they would be good to use in a tone pot?

Incedentally, the blend pot on my bass, a concentric pot, and is basically 2 volumes, is labelled A500K C500K, that suggests to me that the top is audio taper and the bottom is the inverse? and i don't have any problems with volume jumps on that?

Ad if A and C are the log ones, that would make B the linear pot which is the one where i have a sudden volume drop?

iPie · #11 06-05-2011, 02:00 PM

also the bass was made in korea so i doubt they use European nomenclature... not sure though

SGD Lutherie · #12 06-05-2011, 02:09 PM

Quote:

Originally Posted by iPie

extremely confused

I thought the whole point of audio taper was for use in volume pots, because the way we percieve sound is not linear, so the halfway point in a linear taper will not sound like half the volume to us?

Audio taper is so you get a smooth fade, such as with the faders on a mixer.

Linear taper is better on something like a Jazz bass where you want to mix too pickups because the taper is evenly spread out.

iPie · #13 06-05-2011, 02:12 PM

Quote:

Originally Posted by SGD Lutherie

Audio taper is so you get a smooth fade, such as with the faders on a mixer.

Linear taper is better on something like a Jazz bass where you want to mix too pickups because the taper is evenly spread out.

So for a master volume, an audio taper would give a percieved smooth volume change, and a linear taper would give the jump down at about 8?

**line6man** · #14 06-05-2011, 02:13 PM

Quote:

Originally Posted by iPie

I think I may do that, I never get round to those kind of things

I still need to buy some solder which I have run out of lol.

If audio taper aren't used for volume pots, can I ask what the point of them is? because it doesn't seem like they would be good to use in a tone pot?

Incedentally, the blend pot on my bass, a concentric pot, and is basically 2 volumes, is labelled A500K C500K, that suggests to me that the top is audio taper and the bottom is the inverse? and i don't have any problems with volume jumps on that?

Ad if A and C are the log ones, that would make B the linear pot which is the one where i have a sudden volume drop?

Audio tapers ARE used for volume pots. They are the standard taper, and linear tapers are rather uncommon.
You will definitely want to use an audio taper pot for tone controls, btw. Linear tones tend to act like on/off switches, doing nothing until toward the end of the rotation, then suddenly cutting all the treble.

The easiest way to tell then is to buy an audio taper pot and see if it functions differently, and if so, whether or not it works better on the bass.

**line6man** · #15 06-05-2011, 02:16 PM

Quote:

Originally Posted by iPie

So for a master volume, an audio taper would give a percieved smooth volume change, and a linear taper would give the jump down at about 8?

No, there should be no volume jumps on a linear taper. By definition, it's taper runs in a linear fashion.

iPie · #16 06-05-2011, 02:18 PM

but a linear taper in resistance doesn't equal a linear taper in volume level, which has a logarithmic scale?

**line6man** · #17 06-05-2011, 02:21 PM

Quote:

Originally Posted by iPie

but a linear taper in resistance doesn't equal a linear taper in volume level, which has a logarithmic scale?

Which would mean that, worst case scenario, you would end up with the pot doing nothing for a large portion of it's rotation.

iPie · #18 06-05-2011, 02:23 PM

Quote:

Originally Posted by line6man

Which would mean that, worst case scenario, you would end up with the pot doing nothing for a large portion of it's rotation.

but for most of this thread that's what you've been saying audio taper does??

**line6man** · #19 06-05-2011, 02:25 PM

Quote:

Originally Posted by iPie

but for most of this thread that's what you've been saying audio taper does??

What are you talking about? I mentioned in post two that audio tapers can give you a volume jump from 10 to 8-ish.

SGD Lutherie · #20 06-05-2011, 02:26 PM

Quote:

Originally Posted by iPie

but a linear taper in resistance doesn't equal a linear taper in volume level, which has a logarithmic scale?

You aren't really changing the volume, you are changing thee signal level.

Log (audio) taper is made to sound smooth when fading from full to off. But we don't use the volume controls on our basses that way. So you will find that audio taper pots have most of the action from 8-10.