Boost, Overdrive, Distortion, and Fuzz - A Second Look
Everyone knows that boosts, overdrives, distortions, and fuzzes are all different types of effects. But how different or similar are they? And how do you know which to choose?
When I first started using effects, I used to think of boosts, overdrives, distortions, and fuzzes as different degrees of volume and dirt. At one end it is clean but louder. At the other end, it is usually louder, but dirty and gnarly. And there are all different levels of dirt in between. Of course, individual effects also tweak the tone, harmonics, and other aspects of the signal as well as the levels of dirt and volume, yielding many variations of character. That simple concept worked for me for a while as I learned about effects and signal chains.
Eventually, I realized I had a very restricting view of these effects. I was trying to find *the* boost, *the* overdrive, *the* distortion, and *the* fuzz that would give up those magic tones in my head. I was often disappointed with the results. I thought I could plug into one of those effects and my tone (but, alas, not my playing) would suddenly sound like Billy Gibbons, David Gilmour, EVH, Jimmy, Jimi, or Stevie Ray, or whoever. When I tried to research how some of those guys got their tone, the info was often confusing. That smooth, heavy fuzz tone was accomplished with a low setting on a fuzz pedal? Or maybe a fuzz pedal wasn’t even used at all? Really? More internet misinformation? My simple understanding was holding me back. It took a while before a world of possibilities opened up when I took a second look into not only what these effects do, but how you can use that info to get a lot more tone options from them. Some of those options aren’t likely to be uncovered unless you take a broader view of what the effects do in your signal chain.
Start Simple
Let’s take a second look, starting with some simplistic descriptions that are mostly true.
A “boost” is meant to make your sound louder.
An “overdrive” is meant to add some light distortion.
A “distortion” is meant to distort your signal in a significant way.
A “fuzz” is a specific type of heavy distortion, resulting in a nearly square sound wave instead of a nice, smooth sine wave.
That seems easy enough until you actually go plug into some of those effects and use them. Then you might find you have a boost that sounds like a fuzz, a fuzz that can be used as a clean boost, an overdrive that sounds better for your metal set than a distortion does, and all manner of results that contradict the simple definitions above.
We could stop right here and just say “labels don’t matter, you gotta try ‘em”. Honestly, that’s pretty good advice and maybe we really should stop there and let it go. The only problem is that this advice isn’t very helpful, and certainly doesn’t explain the “why”. We can do better than that.
Untangle the Complications
Let’s separate a few things that get tangled up to produce the sound you hear when you try one of these pedals.
Gain
The first is gain. You can think of gain as making your signal louder, but not changing it in any other way. You probably know that simple sounds travel in sine waves and the number of sine waves in a given amount of time, say 1 second, determines the frequency of your tone. A tone that generates 82 waves in one second is 82Hz, which happens to be the frequency of the lowest note of a standard-tuned guitar, the E on the open E string. The frequency corresponds to the “width” of your sine waves. The more waves per second, the narrower they become. But sine waves also have a height. You can think of gain as changing the height of your sine waves. The sine wave stays the same width but gets taller, which is “stronger”, which usually ends up being louder, or shorter, which is "weaker", which usually ends up being lower in volume.
Distortion
“Distortion” is almost too general of a term to be useful. Broadly, distortion is any change to your signal, intended or unintended. That could include the addition of noise, boosting/cutting some frequencies, or otherwise processing or mangling the original signal coming from your guitar. We usually think of distortion as a particular type of signal mangling. It is often difficult to describe, but you know when you hear it. We use words like “crunch”, “drive”, “fat”, “dirty”, “fuzzy”, or other such terms to describe various levels and types of distortion. We set aside other types of “distortion”, like noise, modulation, filtering, adding echoes, phasing, etc and use special terms for them because they sound very different from the “distortion” we have in mind when we’re talking about “dirt”. We’ll continue to use “distortion” in the context of “dirt” here.
Clipping
Another concept to untangle is clipping. Clipping is a common form of distortion. Your guitar signal travels through some electronic devices, such as tubes, transistors, op amps, and other components that internally have their own circuits. These devices require power to operate, and can only operate within their power design specs. Let’s make up an example with an op amp. Op amps are small chips that can do a variety of clever things to your signal, such as add gain and mix different signals together. Let’s say the op amp was designed to operate with a supply voltage of +9V to -9V, and that we are providing that chip with those voltages. Now your signal comes into the op amp, and the op amp performs its desired function on your signal, say adding some gain. As long as your original signal and the resulting signal are between +9V and -9V, and you are using a high-quality op amp, all is well. Your signal gets a little bit louder but isn’t otherwise changed.
But what happens if your incoming signal, or the louder resulting signal, gets boosted so that it falls outside the +9V to -9V operating range of the op amp? The answer is that it can't - it gets “clipped” instead. That means that any signal that would go above +9V gets cut down to +9V, and any signal that would go below -9V gets chopped off at -9V. Instead of having a nice uniform sine wave, you are left with waves that have flattened tops and flattened bottoms, “clipped” to the power operating range of the op amp. Your ears hear this as distortion. If your signal only went slightly out of the operating range, only the very tip-tops and bottoms of the waves would be cut, yielding only light distortion. But if your signal was well out of the range, maybe half the wave would be chopped off, perhaps even more. That results in heavy distortion. If you chop off enough, you may not have enough wave left to hear the difference between waves of different widths (frequencies), and notes start getting muddy and indistinct, chords even more so since there are many mangled notes mixed together.
This type of clipping and distortion happens when you operate something outside its limits, like the op amp in our example. But it could have been a tube. Or a transistor. Or a speaker. Or some other component somewhere in your signal path. Usually, you have some control over this by adjusting a “Drive”, “Distortion”, or “Volume” knob on your effect. Or maybe you can turn your guitar volume down so your signal isn’t so “tall” to begin with. Some effects may let you operate them at higher voltages, which means they will clip less because they are running at a wider voltage range. This wider voltage range translates to what is often called "headroom".
Diode Clipping
There’s another type of clipping that is done with diodes. One function of a diode is limiting the maximum voltage that can pass through the diode. Anything beyond that voltage gets clipped off to that voltage, much like operating the op amp outside its range. Effect designers frequently use a variety of clipping diodes in numerous different configurations to clip and distort signals at different levels as they pass through the effect. They may also boost signals to cause components to overload and clip or change the part of the waves that gets clipped.
Square Waves
There are a couple more pieces of information about distortion and clipping that we should note. If you are just barely clipping the peaks of your signal, you may not even notice it. Your sine waves stay mostly intact. But the more you chop off, the less your resulting signal looks like a sine wave. If you clip enough, you are left with the nearly vertical begin and end of each wave, with a flat line between them. You may not even be able to tell that the vertical parts have any curve at all. This is called a “square wave”. It has a fairly distinctive sound, which we call “fuzz”.
Clipping Isn’t Perfect
In our discussion about clipping, we noted two types of clipping. One is caused by operating something outside its intended range. The other is the more controlled use of clipping diodes. We might have left you with the impression that all that is happening is a smooth “chop” of the signal at some particular voltage. But that isn’t quite the whole story. As you operate devices outside their intended ranges, they are essentially failing. Those failures aren’t always nice and smooth, nor are they always immediate and at the exact same levels. The chopping can be messy, leaving behind a series of tiny peaks and valleys, with gradual or sudden slopes in the chopped part of your signal. And the failures may be slightly different at different frequencies, as heat builds up in the device, or as other conditions are encountered. Even clipping diodes respond at different speeds and handle different frequencies slightly differently. All that messiness gives individual character to the clipping and distortion.
More Clipping Details
At the risk of getting a little too detailed, we’ll just touch on a couple of other aspects of distortion and clipping. A sine wave or any complex sound wave, contains information that our ears detect and turn into music for our brains. Parts of the wave where the shape of the wave is changing the most contain the most information for our ears. Those parts are normally around the very top and bottom of each wave. If you have effects that take in the same signal and clip the waves the same amount, they will tend to sound very similar unless they are doing other tone-shaping operations, such as filtering frequencies. The more the waves are clipped, the more similar the remaining portions will sound. Since all of us have ears that process sounds slightly differently, there are many people that will find lots of these effects sound very nearly the same, particularly as the distortion/clipping gets heavier. Others may hear the slight differences more clearly. If you pay close attention and make small adjustments in volume, drive, distortion, etc, you may learn to hear more subtle differences.
Even if two circuits are clipping the same signal at the same voltages, there are still likely to be differences like the ones described a little earlier – quicker onset of clipping, introduction of a series of little peaks and valleys in the “flat” clipped portion of the wave, etc. These can be caused by the different types and models of components used to produce the distortion. We can often hear those tiny differences, which helps make similar effects sound somewhat different. If those tiny differences are “fast” and have sharp corners and spikes, we perceive them as being harsh. If those tiny differences are “slow” and have more rounded corners and peaks, we perceive them as smoother.
Wave Shapes
Some circuits will even change the overall shape of the sine waves. For example, the leading side of the wave may become nearly vertical while the trailing side falls more gradually. The sine wave begins looking a little more like a series of lop-sided triangles, called a “sawtooth” wave shape since it resembles the teeth on a saw blade. Or the rounded tops of the waves can be made more pointed, producing a triangle wave. Our ears are pretty sensitive to changes in wave shapes and they have unique character to us.
Symmetric and Asymmetric Clipping
There are a couple of clipping methods that are often used. One is called “symmetric”. In symmetric clipping, the tops and bottoms of the sine waves are clipped the same amount. In “asymmetric” clipping, the tops and bottoms are not clipped equally. Our ears can detect the differences when they are great enough. Tubes are imperfect devices. When they begin clipping and distorting, the clipping is often asymmetric. An effect that is meant to capture “tube tone” might well employ asymmetric clipping in its design to mimic the asymmetric clipping of a tube.
Hard and Soft Clipping
There’s also another way to classify clipping configurations besides symmetric and asymmetric. Clipping can also be “hard” or “soft”. In both cases, diodes are used for their voltage-limiting properties. The difference is now they are connected in the circuit. In hard clipping, the “extra” voltage gets dumped to ground and is forever lost, resulting in those flat, lopped-off sine waves. Hard clipping is usually very easy to hear, resulting in a more distorted sound. It is also often accompanied by a volume drop since a lot of signal is cut, unless other measures are taken to restore the volume of the resulting signal.
Soft clipping doesn’t “throw away” portions of the signal in the same way. Soft clipping is usually found in an active stage, where a transistor or op amp is boosting the signal and likely also performing some frequency-dependent filtering. The clipping that results can vary greatly depending on the boost or filtering that may accompany it. Some portions of the signal may not be clipped at all, other frequencies or volumes may be clipped more.
Mixing It Up
And finally, boosting and clipping can be mixed together to produce a big variety of tones. For example, if a circuit is clipping at +2V and -2V (symmetric), the signal could be given a big boost first, so that the clipping removes far more of the information in the sine wave. Or the boost could be small so that more of the original signal is retained. Or you could boost the signal massively, say to +/-10V, then clip most of the wave on the positive side at +2V and only lightly clip the negative side of the wave at -7.5V. That asymmetric clipping will give you a sort of blend of a fuzzy, nearly square wave mixed with a “crunchy” less clipped signal, perhaps with a volume boost. That will sound distinctly different from either approach taken symmetrically. Or the boost could be done after the clipping so that the clipping is much lighter. Or you can have multiple different boost levels and/or clipping stages in a circuit. Or symmetric and asymmetric clipping can be mixed with hard and soft clipping. Add in pre-distortion and post-distortion frequency filtering, and you can imagine why there are so many different boost, overdrive, distortion, and fuzz effects and why they sound so different in different rigs when you add in all the other boosting, clipping, and filtering going on in all those other pieces of gear. And we’re just talking about simple analog effects here. There’s another whole universe of digital effects that can do other things to your signal.
Germanium Distortion
All that messiness is part of why two pedals, even of the same brand and model, can sound very different, even though they are doing mostly the same thing and may even be built from the same parts. Perhaps the most extreme example you may already know about. Many older effects used germanium transistors or diodes to create their boost, overdrive, distortion, or fuzz. Germanium devices had notoriously wide ranges of “acceptable” performance. Two identical effects built with exactly the same components could sound very different. Even if you found two that sounded about the same, using them at different temperatures, such as in an air-conditioned venue vs an outdoor stage in the Texas summer, would cause them to sound completely different because their distortion-inducing properties would vary wildly. Some effects still use germanium components and can have that wild variation in tone. Most use more modern silicon components, which don’t vary nearly as much. But they still have slight variations from one to another within their acceptable spec performance.
The Simple View Again
You probably already see some of where this is headed, so let’s just get it out there. The more gain you apply to a signal, the more likely it is to exceed the operating bounds of some component (or clipping diode) and get clipped, or distorted. The further out of bounds the signal, the heavier the clipping and distortion. Thus it stands to reason that if you want “clean” sound, no distortion, then you probably need low gain and/or components in your signal path that have a wide, unclipped voltage range, which is referred to as “headroom” – your signal doesn’t hit its head on the “ceiling” of the voltage range and get clipped :^) Conversely, if you want a heavily distorted tone, you crank up the gain and make sure you are overloading something in your chain and/or getting your signal clipped in a manner you find pleasing.
You may still be tempted to say that a boost increases gain, but not to the point where there is distortion. Overdrive produces light to moderate distortion. “Distortion” is used mostly to refer to heavy levels of distortion. Fuzz results from distortion so heavy that it produces a nearly square wave. That’s mostly true.
It Isn’t That Simple
But things aren’t that simple. The above ideas will actually guide you pretty well most of the time, but a few more factors creep in to cloud the guidelines. One is that our ears perceive tones unevenly. If you increase or decrease the gain of a signal, it doesn’t seem to affect all frequencies equally. You might well notice a decreased level of highs vs lows when you turn down the volume. Fuzzes can be notoriously dark at low volumes, for example. So that means your ears will perceive the clipping and distortion differently for sounds of different frequencies. If you have a lot of bass in your distorted sound, your ears don’t hear it as distinctly as they hear distorted highs. Distorted bass gets loose and flabby and the notes are sometimes difficult to separate. Many effects try to manipulate (or give you the ability to manipulate) the frequencies that get boosted and/or distorted. There are lots more treble boost effects than there are bass boost effects, simply because boosted bass getting distorted often sounds bad to us. It is unlikely that your boost, overdrive, distortion, and fuzz effects boost or distort all frequencies the same amount. That’s part of what leads to the plethora of those types of effects – designers finding sweet spots to emphasize and/or cut before or after your signal is boosted or distorted.
These effect design choices don’t get applied evenly, though. You’d think a particular effect would behave the same way all the time. In a sense, they do, but their behavior may be more subtle than you expect. The level of boost and distortion can depend on what you are playing. The boost or distortion for a lead guitar part may sound fairly different for a rhythm guitar part an octave or two lower. That can be due to the design choices to boost/distort certain frequency ranges more or less than others. If you aren’t playing in those ranges, you’ll get a different sound from when you do play in those ranges. That’s probably one of the reasons why people have different experiences with the same effect – it depends in part on what you are playing.
Of course, it also depends on how you play. If you have a light touch, you’ll likely have a cleaner signal to begin with. If you really dig in, then you may have a hotter signal that is closer to clipping and distorting before it even gets to your effects. Some effects try to live in the ranges where you can get different levels of “dirt” or distortion simply by playing softer or harder. That can be a lot of fun!
Even Simple Setups Have Lots of Options
Now here’s where the simple rules begin falling apart. Let’s say you have the simplest effects setup possible. Your guitar is plugged into an effect, and the effect is plugged into your amp. Now, not only does different playing style and material affect your signal, but several other things can also come into play. Thicker strings will produce a stronger signal. Different pickups will produce very different levels of signals. You can adjust your signal level with your guitar volume. You can adjust the signal level of different frequency ranges with your guitar tone control. Even the type of pick you use and your guitar’s construction and setup can influence the strength of your signal, getting you closer or further away from causing distortion somewhere in your signal path.
Obviously, we expect boost, overdrive, distortion, and fuzz effects to change our signal, so we’ll skip past the effect in the chain. What’s left? Your amp. And don’t forget your speakers. The front end of your amp is like an effect. It often lets you adjust your tone and your gain. But it is filled with tubes, transistors, op amps, or other devices that behave just like our op amp example. If you send your amp a signal that is too hot, your amp will clip it and/or distort. Or your amp may produce enough gain on its own, particularly in the “crunch”, “drive”, or “high gain” channel, to produce its own distortion. Once that signal comes out of your preamp, it goes to the power amp to be made powerful enough to drive your speaker(s). But once again, speakers behave like other components and will clip/distort if the signal is too high.
It’s Not Just What They Do, But How You Use Them
Next, we get to the part where the simple rules are frequently broken. We’re talking about intent, now, not just capabilities of effects. Yes, that boost effect may increase the gain without clipping inside the boost itself, but the resulting signal may easily be too much for your preamp, causing your preamp to clip or distort. Why would you want to do that? Maybe you don’t. Maybe you want a clean sound and you don’t want your boost to do that. Or maybe if you turn the boost up high enough that it distorts in the boost itself, you don’t like the sound of that distortion. Or maybe you prefer the sound of the clipping/distortion in your amp instead of your effect. Or maybe you prefer the tone-shaping designed into your effect. Or maybe you prefer to adjust the tone with your amp, or with your guitar. The point is that you have lots of choices now for how and where to produce the distortion, how much distortion you’ll get, and what it will sound like. But regardless of how you produce the distortion and what piece of gear causes the distortion, you can’t hear it until you hit a string and the signal comes out your speaker. You may not even really know how/where it happens, but if you turn the right knobs and play the right stuff the right way, you get what you want. Your intent or usage of an effect depends on all the cumulative effects in your chain, which may be pretty different from just what is going on in your effect. And that is why a boost can become a fuzz, a fuzz can become a clean boost, and all manner of mixed behavior finally emerges from your speakers after passing through boost, overdrive, distortion, and fuzz effects.
It can be a challenge to figure out which types of effects you need, and even more challenging to figure out which specific effects to get. Everyone has probably bought an effect based on a video of someone playing it, or even playing an effect at a guitar store, then finding it doesn’t sound the same in your setup. That could well be due to adjustments of the various pieces of gear in the effect chain, playing style, and material, among other things. It may be tempting to trade that new effect in and try the next great thing when that happens. But you may want to take a second look. It may not work, but it can be fun and may turn up some interesting results.
Stacking
When it comes to boost, overdrive, distortion, and fuzz effects (along with your amp), you might try stacking them in different ways and using different tone and drive settings than you might normally use. What is stacking? On a pedalboard, it refers to running out of room for “one more pedal”, and physically having to stack them on top of each other (ha, ha - NOT!) (BTW, that’s not a problem with rack effects… just sayin’…) It refers to trying the effects in different orders. Try that boost both in front of and after your fuzz. Dial the fuzz down and crank up the boost. Dial them both up and turn down your guitar volume. Try them in your amp effects loop so that they are after your preamp instead of before it. Use their tone controls to cut bass before distortion. Try a guitar with different pickups. All of these are ways to change the character of the resulting tone. Chances are that if you are chasing the tone of one of the guitar greats, you’ll find they have some sort of stacking going on. Remember that earlier comment about “you gotta try ‘em”…? It turns out you may have to try them a lot of different ways.
Understand Your Tools
So is a boost just a boost, or is it an overdrive, distortion, or fuzz? In the end it doesn’t really matter too much as long as it helps you get the tone and control you want. But it is good to know what the effect is meant to be on its own. Knowing a boost stays clean through its full range of control is good knowledge. So is knowing that it starts distorting on its own at high volume. So is knowing that it’ll push your tube preamp into some really nice crunch. Or with the stomp of a footswitch your power amp tubes can now give that clean tone that little something-something that makes it hard to put your guitar down when you’re laying down some country or blues.
Knowledge is power and leads to good tone. The guys I know that have good tone often have some good knowledge about their playing style, their guitars, and their amps. And they use effects to tweak and build different tones out of the base tones they get from their gear. Think what it must have been like back in the early 70’s before there were loads of effects to choose from. There were guitars, amps, and a handful of effects. Yet the great players got some crazy-good tone out of those few pieces of gear. They did it by understanding what their guitars and amps could do, then experimenting with using effects in very specific ways to sweeten the tone that came from the fingers, guitars, and amps. It’s still the same today. We have more choices, far more, so it should be easier, not more difficult, to produce good tone. But perhaps we don’t always develop that deeper understanding of what our gear is doing that lets us piece together that magic tone. Unless you happen to get lucky, there are few silver bullet effects that you can plug into and get an exact specific tone you are chasing. There are always fingers, guitars, amps, venue acoustics, and numerous other influences on your signal that must complement each other.
Develop Your Skills With Your Tools
Most players at one time or another have tried to replicate the tone of one of their favorite players. If you’ve done that and used the internet as a source of information (and misinformation!), you know that some of those tones can be captured really well using wildly different setups. One guy can hit it with just a guitar and an amp. The next guys uses a complicated setup with lots of pedals, multiple amps and signal paths, and super-specific settings. Yet a third guy plugs a crappy guitar into a crappy pedal into a crappy amp and gets a 95% accurate version of that tone. And there’s always one guy who thinks he has it nailed, but you don’t think it sounds at all right. All that highlights a fact about audio processing. There are often multiple ways to incrementally shape a signal and get very nearly the same resulting signal. But it is also true that certain things you try may make it nearly impossible to get there. It can be a little like woodworking. You might rough something in with crude cuts, then make finer cuts, and finally sand it to near-perfection. But if you cut your board too short with the first cut, you’ll never regain the length no matter how much more you cut and sand it! Woodworking and sound-sculpting are both crafts. The more you understand the capabilities of your tools and how to use them, the quicker you can achieve accurate results and find different ways to get there if one of your tools is missing.
When you get that new boost, overdrive, distortion, or fuzz, try it by itself first to get a solid understanding of what it does with your playing, your guitar, and your amp. Then think about what that would do to the other components in your chain and try it in different places with different settings to see where it sounds best. And if you’ve been impatient (aren’t we all?) and haven’t really developed a detailed knowledge about the interplay of your playing, your guitar, and your amp, maybe spend some time there. And see what other players are doing. It doesn’t matter how much you think you know about your rig, it seems there’s always someone that knows another trick to try. And take your time, some of the sweet spots are in very narrow control settings on all those knobs and switches in your chain. If you tend to be impatient and try the controls at full off, full on, and halfway to try to get an idea of the tone ranges, you might miss the magic between the 10 and 11 o’clock setting for some config.
Don’t Get Frustrated – It’s Fun!
It may take a while, but you’ll likely discover things about the effects, your playing, and your other gear in the process. You’ll almost certainly develop a better understanding of how effects and your gear work together, making it easier to select other effects or pieces of gear to try in your chain. Keep your eye (or rather your ear) on the end result, but don’t forget to enjoy the sounds along the journey. Don't be "disappointed" to end your journey someplace other than where you intended to go. Many times, we get caught up in trying to replicate the sound of a favorite artist. We all know there can be many, many challenges in doing that. And, yeah, if you don't have the exact right tone for those solos in "Comfortably Numb", then they just don't seem right. They are masterpieces and anything different just doesn't quite measure up. It's OK to accept the challenge and go on that journey. But don't forget that you'll probably play some other music, too. You'll find lots of great tones on that particular journey, so don't hesitate to stop and enjoy them! And you don't have to sound like anyone else to be good! I love listening to live music, whether by world-famous artists with dozens of #1 hits, or good bar cover bands that no one has heard outside a 10-mile radius from my local watering hole. And, honestly, some of the most popular and best-loved music doesn't really have some specific magic guitar tone. There are many definitions of "good" when it comes to guitar tone and there's no shame in any of them when the result has audiences dancing and singing along!
Wait A Minute, You Said Useful Information!
Yes, you're right. All the information above is interesting, and some is useful, but there may not be enough useful information there to select and configure the boost, overdrive, distortion, and fuzz effects for a Gerlt Technologies solution for your signal chain. We'll never have enough information that we can just "calculate" what modules and options you'll need, but we can provide some more useful information. The guidelines below should be helpful.
Bass
You have probably found that some boost, overdrive, distortion, and fuzz circuits don't really sound so good when they are used with bass-heavy signals, either from a bass or even the lower notes on a guitar. That's due to a bad combination of physics and human hearing. Bass tends to get flubby, indistinct, and muddy if you add gain, clipping, and distortion. Check out Bass Effects for a discussion about effects for bass. Just to summarize some of those recommendations, look for effects that give you special control of the lowest bass frequencies in your signal. Effects that offer a mix of wet and dry signal can allow you to add gain up to the point that it starts to sound bad, but augment it with some dry signal to keep your rhythm distinct, yet with enough color to make it different. There may still be some muddiness, but not as much as just the wet signal path alone. There are still "rocks" in the mud that can be recognized! Other effects may offer a completely separate path for low frequency notes that doesn't go through the gain/distortion portion of the circuit. Only the higher notes and harmonics are changed by the effect, then rejoined with your original low notes. That can avoid the muddiness completely, yet provide a lot of upper frequency signal for the effect to manipulate, giving the combined signal considerable color while the notes stay clear. We offer a special module, the Mudslinger, that will let you use this dual-path approach with any boost, overdrive, distortion, or fuzz module of your choice. Many effects that would normally be rejected for bass may work great with a Mudslinger. There are other bits of information in that paper that may help with selecting and configuring modules specifically for bass.
Compares To
Most GT module configurations "compare to" pedals that you know or can find out about. We have many different boost, overdrive, distortion, and fuzz module configurations. Each module description includes information about pedals they "compare to", including in some cases how they may differ. For the most part, at GT "Compares To" means we have specifically tried to make our module configuration sound like the "Compares To" effect. Google, YouTube, your experiences, experiences of your friends, and information about specific artists' signal chains can then guide you to the right module configurations to consider. Most GT modules have options you can select. Those options are described on the modules' pages. You can see the lengthy "Compares To" information by following the menus Products -> Modules -> Compares To at Compares To Options are often meant to change how an effect sounds. Perhaps an effect you would normally avoid would sound good with one of those options. The differences can be substantial enough that you may not agree that the modded configuration really "compares to" the same effect.
More Controls Means More Control
Some effects have very few controls, maybe only 1 or 2. With fewer controls you will obviously have less options for dialing in different tones. If you are considering a couple of different overdrive modules and they have different controls, you may want to consider giving some preference to the one that provides the most controls. Of course, too many controls can make finding and dialing in specific tones very difficult and time-consuming. Consider which specific controls are offered and choose ones that you think will be most useful to you. Have a look through the options that are offered, not just the standard configs. Many of the optional controls are offered specifically to overcome limitations in the control of the standard configurations and can open up a whole new palette of tones from an effect that you may have tried and discarded in the past.
Volume, Gain, Level, Mix, Drive, Distortion
There are numerous controls in different effects in this crude category of controlling the volume and dirt. Most boost, overdrive, distortion, and fuzz effects will have at least one of these controls. Find out what it does or where it is in the circuit. That will help you figure out how to use it, perhaps how to use it with other effects in your chain. You may well find that controlling the "volume" at different points in your chain yields considerably different sounds.
Tone
Many boost, overdrive, distortion, and fuzz effects give you some level of control over the Tone. Often there is a single Tone control, sometimes separate controls for Bass and Treble, perhaps even Mids or Presence. It's good to be able to control the Tone in these effects, for a couple of basic reasons. First, you will probably be changing the overall Volume. Our ears don't hear a uniform change in Tone with changes in Volume. You may need to compensate for Tone differences as you adjust the Volume. Second, the nature of clipping and distortion changes with the frequencies being affected. Tone controls ahead of the clipping and distortion may provide a way to dial in considerably different overall sounds. Tone controls after clipping and distortion may allow you to compensate for tonal changes caused by the distortion. Tweaking the tone at different points in your chain may be necessary to get the overall tone you want at the end.
Circuit Behavior
Some of the ideas listed above hint at some knowledge of the circuit design. Where does the volume get adjusted? Is the tone control before or after the distortion? etc. Generally it takes too much time and explanation to go through that level of analysis when you are buying an effect. In most cases you probably won't be able to get that info from your effect dealer. But there is a wealth of information about many effects on the Internet, and with a little effort you can often find some of these answers. At GT, some of our module descriptions include bits of this information, or maybe we could provide it - just ask! We won't be diving into any detailed circuit analysis, as that is far too difficult and time-consuming. But simple questions and answers are generally "good enough" in this area. The more you know about what happens when you adjust a dial or switch, the easier it is to figure out how and when to use it.
Clipping Diodes
Many effects use clipping diodes for distortion. Knowing the general clipping configuration can be helpful. Carefully choosing optional clipping configs is often a great way to get a different set of tones from an effect. The differences can be subtle to substantial. We often recommend different clipping options as one of the best options to consider for overdrive and distortion modules. Not only do you get a different sound, but it is a simple switch setting, not a position on a knob. That makes it easier to dial in different tones that you might like. It's much easier to get there with a flick of a switch than having to carefully turn a knob to its sweet spot. And if it is switched, it may be possible to make it a footswitch, so you can easily change it as you play.
Active Components
Active components are the ones in your circuit that require power to function. Usually they are transistors and op amps. Transistors and op amps are probably being used to control both the volume and distortion in boost, overdrive, distortion, and fuzz effects. Changing those active components can have a big effect on the resulting tone, or perhaps almost none at all. The choices to change these components can quickly get you down in the technical details, and isn't likely to be very rewarding. But there are a few ideas that are easier to consider.
First, you won't likely be able to swap a transistor for an op amp or vice versa. They are too different in design and physical format for that. But you can swap transistors for transistors and op amps for op amps, within certain bounds.
Op amps are ICs that have a particular "pinout". The pinout refers to the number and location of the pins or "legs" on the IC. To swap one op amp for another, they have to have similar specs and the pinouts (function of each pin in each location) will almost certainly have to be identical. There are a few GT modules where we offer completely different pinout options for op amps. This is usually because the original op amp has an odd pinout and it is difficult to find those old models of op amps. Many times there are current op amps with a different pinout that will sound virtually identical, perhaps even better, so we'll build that option into our boards. But most of the time, you'll be limited to choosing an op amp with the same pinout. For op amps, you won't generally get a huge difference in sound by swapping from one to another. There can be differences, but usually they are not pronounced. Some ears will be able to tell that particular op amps tend to have a warmer sound than others, and you may select a different op amp to compensate for that. Another possibility, particularly for older circuit designs, is that the original op amp that was used is older in design and noisier than a newer op amp. This can be an important consideration for high-gain circuits, where you may really want to avoid any unnecessary sources of noise. Another possibility is that some op amps are relatively "lo fi" while others are "hi fi". If you are looking for a cleaner sound, then an op amp with more "hi fi" specs may be a good choice. Or if some op amp circuit sounds a bit "sterile", then swapping to a crappy lo fi op amp may give you a little more "character". At GT, we don't solder op amps to our boards. We mount them in sockets. If you are careful, you can swap op amps (or have someone do it for you) to experiment on your own.
Transistors are similar to op amps in some ways. Almost all transistors have 3 legs, but those legs have specific functions just like the pins on an op amp. Generally, if you want to swap transistors, you have to choose from among those with the same pinout. Usually, as long as the pinouts match, you can choose from a wide variety of substitute transistors. While you may have many options that will technically work, or at least not fail, you probably will find a much smaller set of choices that will yield good tones. You may be able to substitute transistors of different types, eg silicon for germanium, but those substitutions may require some tweaks to other parts of the circuit. At GT those sorts of substitutions will likely have different configurations. For example, we offer Woodstock module configurations with germanium or silicon transistors that compare to germanium and silicon Fuzz Face pedals. Using different transistor technologies like that can have major impacts to the sound of the effect. Transistors are soldered in place, so they are not easy to change later.
Also, similar to op amps, you can choose transistors that are more/less noisy or have slightly different coloring of the tone. Fuzz fans may very well develop an ear for specific types of transistors that sound especially good to them. Some fuzz pedals are built around very specific transistors that appeal to many players. We'll avoid getting into the "mojo discussion" about whether specific vintage transistors are special in some way or not. If they sound good - go for it, regardless of their "mojo" reputation. But there is one technical property of transistors that is worth mentioning. It is called the "HFE" of the transistor, and has a lot to do with the level of gain (and thus often the level of distortion/fuzz) the transistor can produce. The higher the HFE, the more gain you can get. Of course at some point you can't really hear "more gain", or it starts sounding bad. But there is usually a range of gains in many pedals that produce different tones that sound great to different ears. Thus, if you have an effect that has too much or not enough gain in its control range, you can probably change the range by changing the transistor to a different model.
While changing transistors for tonal preferences is sometimes done, it is probably more likely to change transistors to change the gain. Or in other words, selecting the HFE of the transistor. This isn't difficult, but sometimes it can be a little messy. Particular models of transistors have a spec range for their HFE. You might consider HFE less than 100 as "low", maybe 100 - 400 as "medium", and greater than 400 as "high". There are no official guidelines, so make sure you're on the same page with someone if you are discussing "high" gain transistors, for example. For an imaginary T1234 model transistor, the spec sheet may show a valid HFE range for that model as 100 - 800. That means any specific T1234 could have an HFE anywhere in that range and still be considered "in spec" for quality purposes. That's a pretty wide range. If you picked random T1234 transistors and tried them in the exact same circuit, you could get quite a variety of sounds. That means that if you already have a pedal that you love and it has a T1234 transistor, you might want to get a similar module with a T1234 in it. But because of the wide variety of HFE values, it could sound different. Even two of the same brand and model of that pedal with T1234 transistors might sound different. You would need to know the exact HFE of the T1234 transistor in your pedal so you could match it. But you can't accurately measure HFE of a transistor when it is soldered into a pedal. You need to basically destroy your pedal to get that bit of information - not good! Most of the time the range of sweet values for HFE are known for a particular circuit, if it matters. The range can be found by destroying perfectly good pedals, by experimentation while building, or by other means. That way, if you request a customization to raise or lower the HFE in your GT module, we know what to do. There are also other helpful bits of information. Many transistors have sub-models. In this imaginary case, there might be T1234, T1234A, T1234B, and T1234C transistors. The T1234 ones would land anywhere in the 100 - 800 spec range. But T1234A may be in the range of 100 - 250, T1234B may be 200 - 350, and T1234C may be 350 - 800. That info will also be on the spec sheet, and makes it much easier to select or swap transistors. You rarely need to get super-specific HFE values. Generally "lo", "medium", "hi", and sometimes "really high" within the context of a specific transistor model are close enough for our ears. Vintage fuzz designs are a bit of an exception. The values for those transistors sometimes need to be within a very narrow range.
Just to give a little insight into something you may (hopefully) never need to care about... At GT we stock many different transistors for use in our hundreds of module configurations. We have many thousands of them on hand. Of course, we have to purchase those transistors. For current production transistors, and even many of the older out-of-production silicon transistors, about the only information provided to us as a buyer is the brand and model. Sellers rarely ever measure the HFE of individual transistors, or even a sampling of transistors in a large bulk quantity of them. They will just refer buyers to the spec sheet and say that the HFE should be in the specified range. If it isn't, then maybe you can return them as defective, maybe not. So if we are looking for T1234C transistors and we want them in the range of 400-500 specifically for some circuit, we just have to buy some T1234C (or maybe even just T1234), and hope we get ones with the values we want. If we buy 1000 of them, we may get 1000 "good" ones or perhaps none at all. Sometimes the lot of 1000 will have values scattered all through the spec range. Sometimes all 1000 of them may have almost identical values, either values you want or don't want. You never know what you're going to end up with. We have to keep purchasing until we get the "right" ones. If we run out of good ones, we may have trouble getting more or it may take some extra time. For older and more scarce germanium transistors, this can become a seriously annoying issue. With germanium transistors, there are two parameters that must both land in the correct range. One is HFE. The other is called "leakage". There is no spec value for leakage - it is basically a manufacturing defect. Some sellers will actually measure HFE and/or leakage of individual transistors so you can shop for exactly what you want. Of course you pay a good premium for tested transistors because it is time-consuming to test them. Other times, you just have to buy some and see what you get. Different methods of testing will yield different results even on the same transistor, so even tested transistors may not be the right ones. Since germanium transistors are scarce and increasingly expensive, it is possible we can be out of stock on specific models with the right parameters. But we buy in advance and try to keep good ones on hand. Old, rare germanium transistors with the right values can get pricey. This is complicated because most circuits that use them use 2 or 3 of them, and all of them have to have specific values or specific values relative to the values of the others. Coming up with good sets of germanium transistors can be difficult and is often expensive. In fact, nice tested sets cost enough that they are often fake or counterfeit parts instead of legitimate ones, making it more difficult and expensive to source legitimate parts. Generally, the model matters less than the HFE and leakage, so we usually have alternate transistors that will work as well or better, often at lower cost.