Could someone please explain lin/log pots in terms a caveman can understand?

[Ace Flibble]

I've searched the forums, I've search other forums, I've spent a solid three hours with Google and all it has done is confused me more. It seems like 50% of people say linear pots are smoother and log (audio) pots give a more sudden change in volume/tone while the other half of people say it's the complete opposite. Then invariably someone tries to explain by going in to how control pots work and how the human ear hears the effcts and... gah!

Basically my problem is this: I can not understand any of that technical stuff, I just want to get the bugger to work. I hate hate hate any volume or tone controls where there are 'dead zones' or sudden drop-offs. I want a completely smooth gradient from full volume/tone to absolutely no volume/tone. The guitar in question has a single humbucker and a series/parallel switch as the only other control. Was thinking of using a 500k pot for one of the controls and a 250k pot for the other to warm the tone up just a little bit.

I just want to know whether I should be getting CTS audio (log) pots for this or CGE linear pots to get completely smooth and gradual roll-down for both controls. I really don't care about the theory or technical aspect of it (I honestly wouldn't even begin to understand anyway even if you did explain, I'm a complete thick-o when it comes to electronics), I just want my controls to give me 100% at 10, 50% at 5 and nothing at 0 plus everything inbetween. I trust y'all to point me in the right direction since you seem to know what you're talking about more often than most forums. Thanks in advance!

 

[lidesnowi]

I've searched the forums, I've search other forums, I've spent a solid three hours with Google and all it has done is confused me more. It seems like 50% of people say linear pots are smoother and log (audio) pots give a more sudden change in volume/tone while the other half of people say it's the complete opposite. Then invariably someone tries to explain by going in to how control pots work and how the human ear hears the effcts and... gah!

Basically my problem is this: I can not understand any of that technical stuff, I just want to get the bugger to work. I hate hate hate any volume or tone controls where there are 'dead zones' or sudden drop-offs. I want a completely smooth gradient from full volume/tone to absolutely no volume/tone. The guitar in question has a single humbucker and a series/parallel switch as the only other control. Was thinking of using a 500k pot for one of the controls and a 250k pot for the other to warm the tone up just a little bit.

I just want to know whether I should be getting CTS audio (log) pots for this or CGE linear pots to get completely smooth and gradual roll-down for both controls. I really don't care about the theory or technical aspect of it (I honestly wouldn't even begin to understand anyway even if you did explain, I'm a complete thick-o when it comes to electronics), I just want my controls to give me 100% at 10, 50% at 5 and nothing at 0 plus everything inbetween. I trust y'all to point me in the right direction since you seem to know what you're talking about more often than most forums. Thanks in advance!

Check this out
http://www.youtube.com/watch?v=RdfIZEB2rdM&feature=related

 

[tfarny]

Buy the RS guitarworks 500k audio taper pots optimized for volume controls. They have an excellent, very smooth taper and are worth the extra 10 bucks if you actually use your controls. For tone buy their 500k regular taper pots. They work the best.

 

[TJD]

Buy the RS guitarworks 500k audio taper pots optimized for volume controls. They have an excellent, very smooth taper and are worth the extra 10 bucks if you actually use your controls. For tone buy their 500k regular taper pots. They work the best.

+1 FOR BOTH VOLUME AND TONE

 

[Patrick from Davis]

How the pots sound to people is up for interpretation, but...  Decibels and hearing are a logarithmic scale.  What sounds "linear" to your ears follows a logarithmic function, not a function for a line.  A Linear function, the line I mentioned, is better for an oscillator, like the rate knob on a chorus.  When something deals with volume and how you hear it, generally it is a log pot.  When something deals with rates, or changing something that is mainly volume independent, it is generally a linear pot.  This "wrapped up in a nutshell" bit of knowledge is full of generalizations, so use with caution.
Patrick

 

[dbw]

Thog have big club!  Thog not like linear taper for volume pot.  Thog find that volume knob using linear pot = only half the range of Thog's volume knob useful.  Thog smash linear taper potentiometer!  Thog much prefer a nice logarithmic or "audio" taper potentiometer.  Thog strongest caveman on whole mountain!

 

[Ace Flibble]

Thog have big club!  Thog not like linear taper for volume pot.  Thog find that volume knob using linear pot = only half the range of Thog's volume knob useful.  Thog smash linear taper potentiometer!  Thog much prefer a nice logarithmic or "audio" taper potentiometer.  Thog strongest caveman on whole mountain!

See now that I can understand!

That video helped a lot too. So, looks like audio taper are the way to go. Kind of confused then why so many people have told me it's linear that are smoother but whatever, so long as the result works how I expect it I can't say I care :icon_biggrin: Thanks people!

Buy the RS guitarworks 500k audio taper pots optimized for volume controls. They have an excellent, very smooth taper and are worth the extra 10 bucks if you actually use your controls. For tone buy their 500k regular taper pots. They work the best.

Does brand really make that much of a difference? I can only easily get CTS, CGE and sometimes Alpha pots over here in the UK, rare to find any other brands.

 

[tfarny]

Yes. I wouldn't have recommended them if I didn't think they were better. Tonar turned me on to them and he was right as usual.

 

[OzziePete]

Logarithmic post are also called audio pots - for a reason. They work better for audio applications. Linears are more consistent,incremental increases of signal whereas the log pot will work similar to the way our hearing hears increases in volume. What's the formula? For every 3 dB of increase in perceived volume there's a doubling of power required (ie: a logarithmic formula)?


I still find it strange though that Leo specified linear pots for the Jazzmaster and Jaguar guitar controls. He must have knew that the changes these pots would make would be subtle.  :dontknow:

 

[mullyman]

Logarithmic post are also called audio pots - for a reason. They work better for audio applications. Linears are more consistent,incremental increases of signal whereas the log pot will work similar to the way our hearing hears increases in volume. What's the formula? For every 3 dB of increase in perceived volume there's a doubling of power required (ie: a logarithmic formula)?


I still find it strange though that Leo specified linear pots for the Jazzmaster and Jaguar guitar controls. He must have knew that the changes these pots would make would be subtle.  :dontknow:

Man, no one even came close to answering your question the way you requested. Here it is...

The audio taper will go up slowly as you turn the knob.

The linear taper will go from 0-10 as soon as you turn it on.

If you want no sound at zero, mid volume at 5 and full on at 10 go with the audio taper.

If you want to do the Van Halen Cathedral intro you're going to want linear.

It doesn't really matter which brand you go with as long as it's not some "Made in the Phillipines" piece of crap. Any guitar shop is most likely going to be carrying the major makers.

You seem to know the difference between a 250k and a 500k pot so I won't go too far into it but to keep things simple, if you're going with humbucking pups you'll want the 500k and if you're going with single coils then you'll want the 250k. Granted, that isn't written in stone but it's pretty safe to think like that.
MULLY

 

[Patrick from Davis]

One last thing, On the pots themselves you will often see an printed value like A500K or B250K.  A is for Audio or Log taper, and B is for linear.  The 500K or 250K is the max value of resistance for that particular pot.  There is a, "sometimes used C value," for reverse log pots, but these are generally special circumstance use pots, not ever used to wire a guitar.
Patrick

 

[Paul-less]

Rule of Potentiometers (Po Ten Ti Om E Ter)

Volume Pot: Log/Audio (very smooth, no sudden drop off)
Tone Pot: Linear (same thing, just in a different application)

Humbuckers: 500k
Singles: 250k
Actives: 25k (Seymour Duncan recommends 100k)


If every guitar was wired this way, guitarists could actually learn how to use their controls for playability in a live situation. Sadly, this is not so.

 

[AutoBat]

My fender vintage noiseless are doodled up with 1meg (1000k) pots 'cause that's what they came with.
I'm on the fence about them really, but not worried enough to change 'em.

 

[mullyman]

My fender vintage noiseless are doodled up with 1meg (1000k) pots 'cause that's what they came with.
I'm on the fence about them really, but not worried enough to change 'em.

1000k pots? I bet that thing is really bright.
MULLY

 

[Dan025]

My fender vintage noiseless are doodled up with 1meg (1000k) pots 'cause that's what they came with.
I'm on the fence about them really, but not worried enough to change 'em.

1000k pots? I bet that thing is really bright.
MULLY

they go with the vintage noiseless, not the samarium cobalt but the older ones. my friend had me do his pickguard and bought the vintage noiseless as a set and i was like what's with the pot's? that cant be right... he said you know best so wire it how you want, so i did, i used 250k and a large tone capacitor like a fender should be, those pups were not bright but worked great for blues not muddy at all wired that way. later i asked him where he got those pot's and he tells me they all came in one package with the p/ups.  :doh:

anyway, log for volume

linear+stereo for blend ldeally.

tone is a subject for debate, it is not like the volume as it is not used as a variable voltage divider but a variable resistor, it's apparent linearity has to do with the peak impedance of the circuit which varies with frequency as well as the listeners perception. a 250k volume pot and a 2.5meg tone would not sound linear with any tone pot taper, a linear in that configuration would barely be noticeable until 3/4 of the range was used or more. that said i know a popular combo is to use a linear tone at about half the value of the volume and a small tone cap. if it works for you then go for it..

you can mismatch pots but i would not go more than double or half. there is no perfect formula.. values depend on pickup impedance based mostly on inductance and not D.C. resistance and preference. there are humbuckers that work better with 250k. there are singles that work better with 500k. there are specialty designs that can use 100k, there are hot pup's that need 1meg and noisless pup's that use 1meg to better simulate true singles with fair output. but with most conventional pickup, 250k is for singles, 500k for humbuckers, there have been guitars with 300k or 330k with either a single/hum combo or p-90's in which case you can change a 500k pot value with a resistor or make a compromise or use some clever switching.  

maybe that's not in caveman speak but i figure good information is better than someone giving advice based on opinions and stated as fact.

 

[lafromla1]

there are humbuckers that work better with 250k.

When I called DiMarzio about putting together an Area 58, VV '54 and a PAF Joe on a master tone pot, they recommended a 250k, so I'm glad that you mentioned that humbuckers can work with 250's.

 

[dbw]

I agree those RS Guitarworks pots are great.  If you can't or don't want to get those, Alpha pots are also solid quality, and available cheap everywhere.

Edit: If you get Alpha pots, I recommend getting 50% more pots than you need, because some of them are likely to be kinda weak.  So for my Les Paul I got 6 pots, measured them all, and picked the 4 with the highest values.

 

[Paul-less]

I'm sorry I didn't clearify. My "rules" were just rule of thumb. The majority of humbuckers will sounds very muddy with 250k volume and tone pots. I would say always try out the rule of thumb, and if it sounds too bright, go down, too muddy, go up.

I ain't too good with them words...

 

[Dan025]

^ didn't mean to put you down, it's a good general rule, i work night's and i might sound less friendly when i post after a long shift. i'm still not sold on linear for tone, but i really need to experiment... all my guitars have only log pots and i dont notice a problem.. but it'st time to rewire something anyhow.

 

[Paul-less]

No harm to foul. If you let any "harsh" words effect you whilst perusing forums, you'll end up locked in your closet.

Anyways, what you said wasn't even harsh....