KNOW the Operation and the Different Types of POTENTIOMETERS (Pots) for Electric Guitar: Audio vs Linear, 250K vs 500K. Potentiometers for Single or Single Coil Pickups, and for Double Coil or Humbucker Pickups.
On this occasion we will deal with the topic of nothing less than potentiometers for electric guitar. Since, as we know, taking care of the signal from our guitar on its way to the amplifier is always very important, and if it must go through low-quality components, this will have a negative effect on the signal itself.
In addition, investing in good potentiometers is not expensive at all, since a quality potentiometer is usually between 5 and 8 dolars per piece, and the installation is not very complicated. It is simply a matter of redoing the solders in the same way in which they were previously. You can make notes and photographs before making a change of these components, to keep everything exactly as it was.
But below I will detail the guidelines that we must know before getting down to work, the most suitable types of pots for tone and volume, and the most appropriate for single pickups and double coils. Since in life, everything we do crazy has a good chance of going wrong.
Potentiometers for Electric Guitar: Linear and Audio
There are two types of pots: linear and logarithmic. The logarithmic potentiometer is usually detailed with the letter A, and the linear with the letter B. Both a linear and a logarithmic potentiometer will deliver 0% at minimum, and 100% at maximum.
Regarding this, there is no difference between one or the other, within the same range of qualities. Their differences are found in the intermediate zone between their minimum and their maximum. In linear pots, the resistance increases continuously and progressively, while in logarithmic pots, the resistance increases exponentially.
The human ear is said to be more logarithmic, or exponential, than linear. This is very easy to understand, with an example. If we have a backpack on our back, and another person fills it with sand in a linear fashion like an hourglass would, we will not feel any weight until the backpack has been loaded with a certain amount of sand.
However, if the backpack is loaded exponentially with larger and larger stones, we will more noticeably notice the changes in weight as the backpack is loaded.
Consequently, the audio potentiometer delivers only a small part of its potential towards the middle of its travel, although contradictorily our ear perceives the audio progressively. And towards the end of the travel, the potentiometer delivers most of its potential.
Pot of Audio for Volume
For this reason, logarithmic potentiometers are often used for volume controls, as the ear perceives a volume increase that is gradual, even though it is not.
In fact, the logarithmic potentiometer is simply known as an audio potentiometer.
On the other hand, the logarithmic potentiometer allows us to smooth out the distortion of our guitar without having to lower the volume too much, since a large part of its travel is delivered on the final part of the potentiometer’s path, being able to smooth out the distortion a lot with a slight cut of this control.
Conversely, if the volume control is linear it will deliver too much audible audio at the beginning of its travel. And if this type of pot is all the way up, it won’t cut distortion as effectively if you turn it down slightly, like a logarithmic potentiometer would.
Pot of Linear for Tone
However, the linear pot is often used for tone controls, because an exponential pitch increase is less accurate and effective, and the linear pot performs better in these functions.
In any case, in this guitar thing there is almost nothing 100 percent fixed, since in an instrument, the taste of each one varies and has a lot of weight. So if someone decides to have exponential pitch instead of linear, and linear volume instead of exponential, after what has been shown, they already know very consciously that they should do it in the reverse way as detailed above.
Checks
I have previously commented that the logarithmic potentiometer is generally detailed with the letter A, and the linear one with the letter B. But depending on the age or origin of the potentiometer, these terms can be reversed. So when buying, it is better to make sure that it is a linear or logarithmic potentiometer regardless of the references A or B.
In the event that the pot is already installed, the most reliable thing would be to measure its resistance while we operate the potentiometer. If it increases progressively, it would be a linear potentiometer, and if it increases exponentially, doubling the resistance progressively, it would be a logarithmic potentiometer.
In the case of carrying out the work of installing the potentiometers ourselves, these concepts are vital. In any case, we can always choose to leave this job to a professional who is an expert in these functions, or even an electronic technician can lend himself to perform this function without major problems at a fairly affordable cost, since it would not be a difficult operation.
However, it is always beneficial to know all these issues, to effectively guide the technician or luthier of what we really need. Although in general it would be a logarithmic potentiometer for volume, and a linear one for tone controls.
Electric Guitar Potentiometers: 250K vs 500K
We move on to the subject of kilohms, which in general would also be of two types for passive pickups or standard electromagnetic pickups: 250K and 500K.
The lower resistance 250K potentiometers filter out the higher frequencies, and the 500K ones let these frequencies through better. For this reason, microphones with a dull and poorly defined sound, such as double-coil or humbucker pickups, usually mount 500K potentiometers. And the sharp and defined pickups like the traditional single coil pickups, usually mount 250K potentiometers, to soften these frequencies that could be annoying.
But if we notice that the sound of our guitar is somewhat strident with 500K potentiometers, we can mount 250K to obtain a slightly softer and warmer tone, and vice versa. If we notice that the sound is not very defined with 250K potentiometers, we can mount 500K to have a sharper or more penetrating tone.
Always Check Potentiometer Measurements
Once all these concepts are known, we must review the measurements of the potentiometers before making a purchase, to verify that they are the same dimensions as those of the potentiometers that will be replaced.
We must also review the way in which the buttons are fixed to the potentiometer, since there are grooved and smooth shafts. The splined shafts are designed for snap-on buttons, and the smooth shafts are attached to the button by a small screw housed in the side of the button.
Something to take into account if we want to keep the original buttons, or if we also want to change them.
Push pull potentiometers are typically operated by pulling the knob out to accommodate additional wiring, typically coil-splitting systems on dual-coil pickups.
Personally I don’t like this type of potentiometers, due to the fact that they tend to be too soft, and their adjustment can be very easily modified unconsciously or accidentally.
Better to place a quality standard potentiometer, and install an independent switch for wiring derivation functions.