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i found a site (that i forgot to bookmark) that offered a dual 500k blend balance pot,and a stacked concentric500k/250k pot.i'm basicaly a beginer in the guitar electronics dept.could somebody let me know what the uses of these differant pots is.also i read that a 300k pot is good for a humbucker,is that right.what are the 1g for?maybe i'm asking to many questions at once?

Where in the world are you Loz?
Here's a couple of US sites but there's no point me referring you to a US site if, say you are in the UK, there are easier places..

I got most of these links just browsing this forum BTW, and then there's Google...
from : localhost/answer to your q, the higher the impedance of the pickup coils, the higher the track value needs to be. Generally, humbuckers will use 500k#937; pots, single coils 250k#937;. In a mixed set you should use the higher value. Some manufacturers use 300K#937; and you will also find 470k#937; and 25K#937;. 25k#937; are used by EMG for their active pickups.

You will also find pots with different tapers; this refers to the way in which the track divides as the slider moves along it, or the sweep. the most common are logarithmic (sometimes called audio taper) and linear. Log taper is usually used for volume, linear for tone although some swear by exclusively log, others by linear and ther are some people who reckon it should be the other way around enntirely. Me, i just go with the flow and do whatever makes my customers happy..

Log pots are usually labelled B and linears A, i think. There is also antilog taper and these are labelled C but you don't see these very often.

It is more about orders of magnitude than exact values; 250k#937; pots will work with humbuckers and vice versa but may present a different taper to the sweep so with the wrong value you may get a bit of a quot;stepquot; in the gain as you turn it up and down. 25k#937; will not work with ordinary high impedance pickups as, if you think about it, it would be like having the volume control of a 250k#937; turned down to 1/10th of its value. As 7turns (see post below) says there is also an effect on the tone, although this is more of an issue with the tone pots than the volume controls. Any circuit which has a resistance and a coil or a resistance and a capacitor or all three, will have a resonant frequency to which it best responds; this is called the q-factor. Altering the value of any of the components of the circuit will alter the q-factor and therefore the perceived tone of the circuit.

The pot in a tone control is really just a variable resistor placed between earth and a capacitor. (pot is short for potential divider; I'll explain this later!)

Capacitors are good at passing high frequencies but don't like low frequencies, so without the resistor the high frequencies will tend to drain to earth. By altering the value of the resistor, we can control how much of the HF component of the signal is drained to earth, and therefore the percieved tone. this is called a low-pass filter. The higher the value of the pot track, the higher the value of the cut off frequency above which high frequencies are lost. The highest value of pot usually found in guitars is the 1M#937; (twice the value of a 500k#937;)found in early Telecasters, Broadcasters, Jaguars and Jazzmasters.

How the pot is wired also makes a difference. The volume control is usually wired as a potential divider: the signal goes to one end of the pots track, the other end goes to earth (so that the track is in parallel with the coil in a guitar circuit). This creates a potential gradient (in DC terms) across the track which is then quot;tappedquot; by the slider, so that if you have a pickup with an RMS value of 200Mv, the output from the slider will be 200mv near the input track terminal, zero at the earth terminal and proportionate in amplitude at stations in between. to be continued

It's all about how much treble you want or don't want. A 250k pot will be warmer than a 500k pot which will have more treble response. A 300k will sound pretty close to a 250k. You can use what you want with your pickups. Traditionally 250k are used with single coils and 500k with a humbucker since its a warmer pickup and doesn't quot;needquot; a 250k pot. But you can do as you like.

You can also control how much treble your tone pot bleeds off by adjusting the value of your capacitor. Traditional hum set ups use .02 but you can go up to .05 to reduce the treble by bleeding off more. An electronic supply store should have an assortment of capacitors in values other than .02 and .05. I'm recalling .039 and other values higher than .05 when I was in one a couple weeks ago. Don't worry about voltage values, just get one that fits in that small space you have to work with. The voltages of the capacitors will be more than enuff to handle what's in the guitar.

Some of the others can give a better techinical definition but I think I'm in the ball park....

continued from above
The problem with a potential divider is that when you have two parallel circuits, as in a Gibson Les Paul, reducing the one potential divider to zero also shorts out the other pickup when they are both in circuit. For this reason instruments such as the Jazz bass use a variant called reverse feed (well, I call it that, I don't know about others). In this the signal goes to the slider and the output is taken from the track end opposite the earth tag. This has the advantage of leaving a resistance between the earth of each pot (buffer resistance) and the signal terminal of its neighbour so that the volume controls operate independently. It is in this circuit that the treble bleed capacitor is most useful as the increasing buffer resistance in the reverse feed pot reacts with the tone control to shunt h/f to earth as the volume control is turned down.

Sorry about the split post but in my enthusiasm to communicate everything I know about the subject in one go I exceeded my maximum allowable post length.

Phew! Any questions?

I have a question, if i have two 'buckers (Jazz/custom) and i have 250K pots... will my guitar still sound good?

thats the way the telegib was wired

jazz/jb with 250k pots. in a fender style guitar i think it can work fine. i dont think it would work as well in a paul


Originally Posted by lozano71i found a site (that i forgot to bookmark) that offered a dual 500k blend balance pot,and a stacked concentric500k/250k pot.i'm basicaly a beginer in the guitar electronics dept.could somebody let me know what the uses of these differant pots is.also i read that a 300k pot is good for a humbucker,is that right.what are the 1g for?maybe i'm asking to many questions at once?

Since no one directly answered your questions…

1. A dual blend / balance pot consists of two potentiometers controlled by one shaft.
Some dual blend pots come with a center detent (for setting the middle point of the pot’s range) Used when it is necessary for both pots to track each other.

2. A stacked concentric pot consists of two potentiometers controlled independently by two shafts (one hollow outer shaft and one smaller inner shaft) They can be used to control two functions while only requiring one hole in your pickguard. (i.e. two separate tone controls or a tone / volume control)

3. As stated by others, a pot (variable resistor) and a capacitor make up a ‘band-pass’ filter.
That is a filter that allows only a certain frequency to pass.
In a typical guitar tone control, the frequency that is allowed to pass is shorted to ground and removed from the guitar’s output.
Since the pot makes up half of the filter, changing its value affects the range of frequencies that can be passed.

Typical pot values are 250k for single coil pickups and 500k for humbuckers. Other values are available to give you more variation / range options.

what if you have a hum in the neck and bridge on a strat, and a single coil int he middle, can you just wire the hums to there own 500k volume and tone pots and the SC directly to its own 250k volume pot? would that sound good?


Originally Posted by unleashthejaywhat if you have a hum in the neck and bridge on a strat, and a single coil int he middle, can you just wire the hums to there own 500k volume and tone pots and the SC directly to its own 250k volume pot? would that sound good?

You can but you will be better off with a 500k as the circuit will default to the lowest value pot when the outputs are combined.

Chaos, a variable resistor and a capacitor forms a low pass filter, not a band pass. Band pass filters require the addition of an inductance. I know that technically the pickup is an inductor but in this context it doesn't strictly form part of the filtration circuit other than serving to derine the q-factor.

I didn't deal with the issue of the the concentric pots as this is really an ergonomic feature and it seemed to me that the question was more about pot values than how that are arranged but thank you for addressing the bits that i missed out

whew,thanx for all that info.i need to go over it all a few times more i think.

[QUOTE=octavedoctor]You can but you will be better off with a 500k as the circuit will default to the lowest value pot when the outputs are combined.

so if i use all 500k pots what do you suggest i use in the middle that will give me a strat sound?


Originally Posted by octavedoctorChaos, a variable resistor and a capacitor forms a low pass filter, not a band pass. Band pass filters require the addition of an inductance. I know that technically the pickup is an inductor but in this context it doesn't strictly form part of the filtration circuit other than serving to derine the q-factor.

I’ve always used the term “band-pass” generically since it does not specify which frequencies are passed. It can encompass low-pass filters (low to 0) high-pass filters (high to infinity) but most commonly both (used together to select a range of frequencies between the two)

A band-pass filter can be constructed without an inductor.
Example: from : localhost/sub.allaboutcircuits.com/images/02121.png
so a stacked concentric pot would be great for me ,since i only have a volume control.i want to ad a tone pot,so i'll go that way.one more question,duse treble bleed meen you lose treble when you turn down the volume,or does it meen it stays the same?remember i'm a newbie to this,thanx.


Originally Posted by lozano71so a stacked concentric pot would be great for me ,since i only have a volume control.i want to ad a tone pot,so i'll go that way.one more question,duse treble bleed meen you lose treble when you turn down the volume,or does it meen it stays the same?remember i'm a newbie to this,thanx.

Yeah, dual concentric pots are useful when you want to add more functions without more holes.
Here is a Gibson V with three dual pots:
Knob1a = neck volume / Knob1b = neck spin-split
Knob 2a = bridge volume / Knob 2b = bridge spin-split
Knob3a = neck tone / Knob 3b = bridge tone

When you say #8220;treble bleed#8221; are you referring to the tone control or the common modification to prevent treble loss when you turn down the volume?

sorry for taking so long to get back heer.what i ment by treble bleed is well,basically ,i do'nt want to lose treble as i turn down the volume.)is that when that happens(lose of treble) is that considered quot;bleedquot;?i want to be able to lower the pickups output,but not lose tone.hopefully,somebodys still watching this post.

Sounds like you want to add a small .001uF capacitor across the volume pot.
The cap would connect the wiper terminal (center) to the outer terminal that is connected to the pickup output.

Here is an example:
from : localhost/#8211; the resistor isn#8217;t necessary unless you want to change the range of the pot)

by changing the range,is that the frequincy range?is it to give more highs or lows?its cool that all these differant options keep openning up.thanx for not being bothered by my questions.

The addition of a resistor shown in the Stewmac diagram will reduce the value of the potentiometer.
Choosing a smaller value cap will reduce the amount of treble retained when you turn down the volume (some think .001uF is too much)

Remember that the goal is to reduce treble loss on your volume control, not make the volume control into a tone control.

thanx chaos.i am kinda starting to get an understanding of all the options i have.basically i have a quot;hot railsquot; for neck and four conductor kent armstrong humbucker for bridge.trying to figure outwhat parts i need to get ,to totally do a differant wireing job on my guitar.i figure another week or so and i'll be able to make the right desitions.thanx for all the info ,people.i'll be asking for more info as i come along(hopefully i wont ask same thing twice).