+86 400-003-5559 CN


Axe Hacks: Spinning Knobs And Flipping Switches | Hackaday

tagselectrolytic capacitor values

From a guitar playing point of view, the two main parts we are most interested in are the pickup and the volume/tone control circuit, which allows you to adjust the sound while playing. Today, I will delve into the latter part and carefully study the components involved (potentiometers, switches and some other passive components) and show their functions, what alternatives we have and how to redesign them. All of them.

In this sense, it is time to heat the soldering iron, take out the screwdriver, remove the toggle guard/open the back cover and continue our search for new electric guitar sounds. And, if it sounds so uncomfortable, skip the soldering iron and grab some alligator clips and breadboards. It may not be an ideal environment, but it will work.

If you missed my last article, 

. To recap: the wire rope vibrates on the magnetic field of the pickup, generating an electrical signal shaped by all the internal characteristics of the pickup. Then, the signal is sent from here to the output jack through the volume and tone control circuit, from where we can amplify and change the sound as needed.

Before starting, I want to say a few words about the guitar wiring diagrams you will encounter on the Internet and the general state of electronic terminology in the guitar world. Since the average musician is not necessarily proficient in electronics, practical schematics are rarely used to describe wiring, and the most common is a visual representation with realistic pictures, similar to the Fritzing breadboard view. This makes it easier to rebuild and implement the wiring itself in practice, but in fact there is not much knowledge about the electronic equipment behind it.

Similarly, for some reason, "nano" seems to be a taboo, because the value of a capacitor is usually expressed in microfarads, while a 22 nF capacitor is usually called 0.022 uF, or simply a "dot-oh-twenty-two" capacitor , Written as ".022 mfd" in the worst case. Although picofarad seems to work, a 2.2 nF capacitor becomes 2200 pF.

According to experience, the capacitance value in guitar wiring is rarely higher than 100 nF or lower than 100 pF, so it should help decipher some more exotic terms. With this in mind, let's get started.

A typical volume control circuit consists of a potentiometer, the signal of the pickup is on one terminal, the ground is on the other terminal, and the output signal is on its tap. When it is set to 10, the resistance of the tap is the smallest, the volume is the largest, and 0 is discarded for the entire signal.

On the other hand, the typical tone control is a low-pass filter made of another potentiometer and a capacitor. When it is set to 10, the potentiometer is at the maximum resistance, almost ignoring any influence of the capacitor. As the resistance decreases, the capacitor begins to suppress the treble, and thus begins to affect the pitch, until it is fully engaged at position 0. The higher the capacitor value, the more the total high frequency suppression (or the lower the resonance peak shift). ).

There are too many in theory, but in practice there are one or two issues to consider. On the one hand, the potentiometer will not be completely reduced to 0 ohms, but it will always have very little static resistance. Therefore, even with a small volume regulator, it will affect the output signal.

Similarly, volume and tone control are not two independent systems, but affect each other. One of the results is that the high level may be slightly lost when the volume is lowered, depending on the actual wiring method.

For example, Gibson Les Paul (and other guitars that provide individual tone and volume control for each pickup through expansion) can have a "modern wiring" or "50s wiring" setting, where the tone control is connected to the volume Control input and its wiper.

With modern wiring, you will feel a slight loss of treble, while with 50s wiring, the tone will hardly be affected when the volume is reduced. However, since everything is connected, it is not without consequences. The table has been turned over, and now the volume control will add some treble when using the tone control. If you rarely use tone control, this may not be a problem, and the wiring from the 50s may be ideal for you, but if you rely on the dark turbidity of bass tone control, it may not be a problem. So happy.

Without overly affecting the tone control behavior, another way to deal with high pitch loss is the so-called

This circuit essentially adds a high-pass filter to the volume regulator. In the simplest form, it is just a capacitor connected in parallel with the input terminal and the tap. Some manufacturers even use this capacitor in the spare wiring of some models. For example, Ibanez uses 330 pF here, G&L 200 pF, and PRS drops to 180 pF. However, higher than 1 nF may produce quite harsh, too bright tones without the risk of too many low points at all. For more options, there are alternative versions that use parallel or series resistors.

The values ​​in the diagram above are more of a starting point, and some experimentation may be required to find a perfect match. The actual behavior of the controls (including treble behavior) also depends on the potentiometer used, or which taper.

Potentiometers commonly found in guitar controls have different types of taper, that is, the part that actually causes its impedance. The two most common types are linear and logarithmic (or audio) tapers, followed by inverse logarithmic tapers occasionally. As the name suggests, their difference lies in how the resistance value changes according to the position of the tap, so as to increase linearly or exponentially (or decrease in reverse logarithm).

As far as volume control is concerned, a linear potentiometer set to 5 (ideally) will have half the output signal level, but considering the non-linear volume perception of the human ear, it will not be equal to half the volume. Therefore, it is usually recommended to use a logarithmic taper for volume control to match this behavior (hence the alternative "audio taper" name), but this also raises the question of whether the guitar volume is real

Is the volume reduced by half when set to 5?

Well, to answer this question, it mainly depends on how you use the volume adjuster and how you want it to work. Some people may stay in the 10-6 range and want to make obvious changes without much movement, while others will sit idle at 6 and then increase it everywhere to increase it casually. Some people amplify the amplifier to its maximum and use the volume knob, just like on an old TV or radio, while others marvel at the perfect dust gradient formed on it. Therefore, it is not surprising that linear or logarithmic taper is the right choice for volume control, although the manufacturer is probably not always determined for economic reasons.

It is similar to the taper selection for tone control, although most seem to be opposed to it because it actually results in a more stable overall scan. But the tone control is also a little different, because their lower settings are still very practical, and even down to 0 is an effective option, and is used regularly in certain styles. This is different from the volume control, which just keeps silent. Anything below 3 may also have limited use. Nevertheless, this does not mean that linear taper is not the right choice for you. Compared to the log taper, its sudden drop into the dark may provide you with some tone-based effects.

After all, the purpose of all these operations is to modify the tonal behavior of the guitar, so we should not limit ourselves to what seems to be a normal way of operating with controls. Although the taper behavior is a fixed characteristic of the potentiometer itself, it is still just a resistance. Will your pitch pot set to 0 become dull and muddy? Maybe try an additional resistor in series to prevent it from dropping all the way to zero ohms. The sound of the 500 kOhm pot is too bright to satisfy your taste, but the 250 kOhm just lacks clarity? Maybe 2.2 MOhm in parallel with 500 kOhm can make it sweeter. Well, try and see what happens.

Okay, so the potentiometers have different tapers and of course different values. Some may have unique, custom taper behavior, or

The problem of "even at zero, there is still a slight residual resistance" is avoided by making the taper completely out of this position. However, for these issues, people again diverged, because it is a good thing to get the original pure signal from the pickup, but once the taper returns to the system, it will also increase some unnatural response.

In addition to the overall size of the potentiometer and the physical characteristics of the shaft structure, the potentiometer does not have many other advantages. So how do you put two of them in a single house? Okay, then we either

Or a


)Potentiometer. Both are essentially two pots stacked on top of each other, one single-axis rotation with two independent tapers. Each potentiometer can usually be used separately, so each potentiometer has a separate connector.

Let's take a simple single-volume, single-tone control line on a guitar with two pickups as an example. Perhaps the bright bridge pickup may occasionally rotate on the tone, while the neck pickup remains the same, and you don’t like the muddy sound of the low-pass filter on the neck. Using a dual potentiometer with two identical potentiometers (for example, linear 500 kOhm) allows you to connect each pickup to its own volume potentiometer, and the tone controls are only connected to the potentiometer of the bridge. Maybe add a treble bleed circuit, which will only affect the neck pickup when you use it.

Or, one of these pickups is a coil, and the other is a humbucker, and a dual potentiometer with 250 kOhm and 500 kOhm can handle their differences with a single control.

For example, fenders have some HSS Stratocasters (for example, a Stratocaster with a buzzing sound on the bridge, and usually two single coils in the middle and neck), the latter arrangement separates the two tone controls of the Strat for Single coil and Humbucker. Since the potentiometer uses a single axis, there is no difference in actual control.

Unless you want to do this, in this case, you can also use

Potentiometer. It is still two separate, stacked to fit the space of a single potentiometer, but this time, the shaft has an inner log and an outer log, and each log can be rotated separately.

Assuming that what you want is not the Gibsonesque method of the guitar, you can control the pitch and volume of each pickup in the guitar separately. Of course, you can use power tools, but this is definitely not something that everyone can drink. If we think of a Telecaster with a metal plate and a fairly limited control chamber space, it may be more difficult. Concentric potentiometers can save! Okay, you will need a special knob to manipulate the two separate axes, but you can install them both in the space of a single potentiometer without any other extensive modification. The original Fender Jazz Bass actually had this configuration, and then switched to today's universal bass cable with two independent volume controls and a main tone control. Which one takes us to stir the pot.

The hybrid potentiometer is a special type of "two potentiometers in one housing". It is the potentiometer you find as a balance control in an audio amplifier, usually with a little gap in the center. In theory, you can use them to mix two pickups together instead of using two separate volume controls. But, at least for passive controls, this sounds better than anything of actual value. In fact, you may neither hear the pure bridge sound, nor the sound picked up by the neck, because another sound will always seep into the signal slightly, and worse, you may end up in the center There is a noticeable drop in volume at the location. (Although I might just simply mash my own wiring, or I should use another mixing pot.)

Please note that there is another "hybrid control potentiometer" wiring, which is also related to mixing the pickups together, but stems from the early development of Telecaster and has nothing to do with the above-mentioned hybrid potentiometer. Although this one is actually pretty cool, so I will talk about it again.

An interesting change of the conventional potentiometer is

An additional DPDT switch is installed on it. The switch itself is completely separated from the potentiometer, but the switch mechanism is activated by pulling out and pushing in the shaft of the potentiometer. A similar variant is the kill switch potentiometer with an integrated momentary SPST push button switch, designed to temporarily eliminate the signal by shorting the signal to ground to produce a unique effect (for example, Buckethead overuses the signal).

Switches are an incredibly valuable asset when tapping a guitar, because they allow us to enable and disable individual modifications as needed (increasing the total timbre of the guitar compared to fixed wiring) and open up more things that cannot be obtained with a potentiometer alone. Choose us very far. Like, why choose to use 22 nF or 47 nF capacitors for tone control at the same time, if you can use both at the same time, and switch between the two capacitors as needed. Or suppose you have found an amazing and optimal position on the tone board, instead of finding it again after tedious attempts every time, use a switch to bypass the tone board and use the exact one you are looking for Value of fixed resistor. Why not completely bypass the control and get the original pickup signal? Not to mention here we can use the pickup to do something by ourselves, but we should not surpass ourselves.

The beauty of using a push-pull potentiometer here is that you don’t need to drill any extra holes in the guitar body to add switches, but just replace an existing potentiometer with it and keep all the original controls as -Yes. And, if you are willing to sacrifice the tone board completely, you can do this further by using a rotary switch of matching size, instead of switching between the two options, you should choose one of the largest switches that fit the control cavity. For example, BB King can choose five separate filters on his Gibson ES-355 (and a sixth bypass option), which Gibson is currently using as


Of course, if you don’t mind making some major modifications to the guitar body, then if you run out of other alternatives, then the standard mini toggle switch is always a solution. On the other hand, there is another switch you might not think of here: the pickup selector switch. Now, yes, removing the option to activate different pickup combinations seems a bit counterintuitive in terms of expanding the guitar tone, but let me go back to the Telecaster mixing controls mentioned earlier.

As early as 1950, Fender released their first electric guitar,

, With single-bridge pickups. Although there is only one pickup, it is still equipped with a three-way selector switch. So, what does that switch do because it obviously doesn't switch between pickups? Well, it basically chose the tone control behavior.

When the volume control is always active, the tone control is active and is completely bypassed or replaced by a fixed low-pass filter, which will produce dull bass. Please note that the double bass was almost the only stringed instrument that could be used to play the bass line at the time. It was a big chunky piece of furniture that could not just be inserted into an amplifier. Therefore, until the electric bass becomes a reality a year later, it is a good choice to tune the guitar to the extreme.

Soon after the introduction of Esquire, the original Telecaster was released (titled

At that time), the appearance was similar to Esquire, but with the addition of pickups. At that time, the three-way switch may have been changed to the pickup selector as we know it today, but Leo Fender wants to retain that deep bass selection so that the switch position remains the same (unless it uses a hotter, which can now be pressed Nature chooses a darker neck). However, the other two positions are now selected when the pickup control is the normal tone control pickup or the bridge pickup (here, the tuning control) becomes the mixing control described above. What it does is to gradually mix the neck pickup signal into the bridge pickup signal, transitioning from only the bridged 0 to the "middle position" of 10, and any value in between, creating some unique combinations.

Nowadays, TV broadcasters rarely think about this kind of mixing control-most players don’t care about the deep bass anyway, so with the 3-way switch eventually it becomes a regular pickup selector, in fact No longer need mixing control. However, Stratocasters may use it occasionally, which makes sense. Recall that the Stratocaster has three single coils, a 5-way switch that does not allow all possible combinations, and a somewhat weird tone control setup, where two pickups have separate tone potentiometers, and the third pickup does not. Change one pitch knob to control the overall pitch, and then turn the other into a mix control, and you will get an otherwise impossible neck or a combination of all three (of course, unless you use a switch, otherwise) a perfect fusion of partially participating pickups.

Again, next time I will cover pickup wiring in more depth, but at the same time, as a sneaky idea, an interesting view of the concept is that there is a hum that exposes the wires of both coils ( This allows you to use it as two separate wires (coil pickups) and apply hybrid control on these two coils. Therefore, you can turn a pickup from a single coil into a complete humbucker instead of mixing two separate pickups. In fact, the Fender Jaguar HH (ie dual humbucker) model is equipped with such wiring, and it is still an interesting tool in terms of wiring.

As shown above, not only can the potentiometer be used to control the volume and tone, the pickup selector switch can also be used to select the pickup, so there are other options for selecting the pickup. In addition, how to use some small toggle switches to enable and disable the pickups (for example

), and then switch the pickup selector switch to a Varitone style filter selector?

When we discuss it, why not completely abandon the low-pass filter and replace it with a high-pass filter? I have already mentioned that the tweeter bleeder circuit is one of the options, but the conventional tone control itself can only have parallel capacitors instead of the usual series wiring. Therefore, now there is no need to lower the high point when turning the pitch knob and cut it off. If you have two tone control potentiometers (or you can choose another), why not use these two options at the same time? Or throw an inductor and cut off the middle part with some band stop filters? As I mentioned last time, mathematical formulas will not get you to this point, so you might just conduct some experiments, put some random things together (extend) together, and see what happens.

And further expand: the diode! By limiting the forward voltage in the signal to the upper limit, routing two of them in opposite directions between the signal and the ground can add a little tightness to your voice. Of course, this will not replace the actual effects pedal, it is still just a passive electronic device. Modifications like this will make you lose some signal, but it is still fun to do so. Keep in mind that even though the average pickup only produces a few hundred millivolts of signal, the forward voltage drop of conventional silicon diodes is usually too high, and germanium or Schottky diodes will bring you greater success. For more information and how to use the full rectifier mode (the commercial version does not cost $30+),


Well, this covers the various potentiometers and various potentiometers we find in guitars, and how to use them with switches to modify volume and tone controls. Of course, this topic is not completely exhausted, but I hope this will give you some new ideas about trying out electric guitar wiring. Most importantly, you can avoid thinking at all. As long as you avoid using external power sources and avoid soldering directly on the pickup coil, you and your guitar will do.

Next time, we will bring the same spirit back to the pickups and forget everything I said about "the hum is two single coils in series" and "the middle switch position connects the two pickups in parallel".

The hackaday logo guitar is outstanding :)

Coming to Tindy!


This is my lucky day. I am making my first guitar. I decided to build my own wiring from scratch because I own most of the parts and I am more an electronics enthusiast than a carpenter. (I cheated and bought a "case" for Epiphone Les Paul Studio with a fixed neck)

One resource I found very useful is Seymour Duncan's website for wiring. They have many non-standard circuit variants, but the wiring diagrams are easy to read.

Stewmac has very basic guidance on certain terms in the guitar wiring world. It helps to find the correct keywords for the components on ebay and aliexpress, and to understand how the push-pull potentiometer works (this is not something I encountered before).

I would say that taking shortcuts is not ashamed. Of course, a guitar carved by hand from a tree growing in the backyard of your childhood home definitely has a more special meaning than a guitar made with a kit, but using the power tools on the kit will make you run wild. I guess both have their place (I haven’t sculpted one from scratch myself-maybe there is an old sauna bench here)

But yes, the Seymour Duncan website is a great resource, and I will make sure to reference it in the next section.

I wish you a happy wiring :)

I can say it again. It's time to make the electric guitar contain more than 2 lids and a switch. Lithium battery with onboard digital processing, power amplifier and speakers. I keep going. We don't all play like Charlie Christian. Radios or phonographs have "tone" controls, and now we have 10-band EQ and more. Compared with today's audio connections, guitar pickups have a fairly high impedance, which makes it easy to complete these ancient techniques. Mega-ohm potentiometers are a bit scarce now, and 500K is not used even in modern electronic products.

Gibson Les Paul is set for high gain (metal, hard rock), it has 4 potentiometers, 2 caps, and active pickup with transistor/op amp and 9V battery. When the most amazing distortion occurs, it sends a very hot signal to the amplifier.

I think that if your bass/midrange/treble controller has a movable center in the center, most music does not require a multi-band equalizer. It is easy to find the desired sound. Most EQs are a bit too subtle due to the usual use of band-pass filters. It is usually good for pure sound, but it prevents some "bite".

If you are not satisfied with 500K, you can exchange custom sizes of 250K or odd balls. But I admit that the guitar circuit is very old-fashioned. The reason is that the output does not come from the branch of the transistor (BJT, MOSFET, etc.). No matter what kind of guitar you plug in, the medium and high impedance output of ordinary guitars will play a big role. Guitar + cable + amplifier is the analysis circuit. Although once you plug yourself into the pedal, the enhanced part of the pedal converts it into a modern and beautiful signal. Integrating the booster pedal into the guitar will be very simple. If you want to search for a specific retro tone, it will cause you trouble. But you will find this installation very convenient for performances. Then, you can plug in devices that are not under your control at random locations. (Or bring the pedals instead of modifying your good guitar-the same goes for the electrics)

Our instruments do have these things, but they are not built into the guitar.

I guess VOX guitars are generally heading in that direction.

Historical point:

"In addition, for some reason, "nano" seems to be a taboo, because the capacitance value is usually expressed in microfarads, and a 22 nF capacitor is usually called 0.022 uF, or simply "point-oh-twend-20". A "capacitor, written as ".022 mfd" in the worst case. Although picofarad is also possible, a 2.2 nF capacitor becomes 2200pF."

When I was in college, most of my professors were still learning to say "pico" when talking about capacitors, not micro.

It wasn't until the 1990s that nano-real tools gained the cap value in the US market. Even in the mid-2000s, I marked the components (usually ceramic disc covers) with the old 0.1 of 100nF instead of 104 ( 10 discs). This is followed by four zeros (Pika Faraz), and the catalog value is also listed.

In essence, the initial statement said that the guitar world has surpassed the 1980s, which is not surprising.

Interesting, thanks! It wasn't until the late 90s that I started to touch electronic products, so I have never seen ancient values ​​outside the guitar world. But it makes sense now, yes.

I noticed that my compact box uses a pair of LEDs instead of Schottky diodes. I think this will provide you with some semiconductor options, because different LED colors will use different semiconductors. My schematic requires red, but I don't know what will happen if I put some blue in it.

My understanding is that in terms of tone, it’s all about the voltage threshold—how hot the input signal needs to be to drive it to clip. The traditional red LED is about 1.7v, while the silicon diode is 0.7v or germanium is 0.3v. Since the range of blue LEDs can be between 3.2v and 4.5v, embedding them may not be of any benefit unless you prepare a serious preamplifier in advance (or, I think, if you want to Use it under 5v voltage) Eurorack level).

I think [Taper Wickel] is similar, and depending on the signal level in the box, the tightening effect will be set later (the gain knob will not have any effect in the lower area) or not at all. In other words, using conventional diodes (or Schottky or germanium) may clip prematurely and be fully compressed at low gain settings (although I am not very familiar with the actual operation)

PRS = Paul Reed Smith. I hope you can talk about installing a phase switch, this is probably the simplest modification you can make.

Excellent as always! I really look forward to these guitarists. The message boards are full of bargaining. It's nice to see decent, detailed instructions without completely ignoring the art and nuances.

Please be kind and respectful to help make the comment section great. (


The site uses Akismet to reduce spam.

By using our website and services, you expressly agree to our placement of performance, functionality and advertising cookies.