- The Effects
- Going Deeper
- See Also
Guitar pedals! Small metal boxes wearing knobs and filled with magic.
These devices were created to give electric guitarists easy access to audio effects in the signal chain between themselves and their amplifier. If you already play your fair share of electric guitar, chances are you probably have a few pedals of your own. But as the majority of our BotBrs generally work in electronic music, this article will focus on the use of guitar pedals outside of the context of electric guitars. Note that sometimes you may find guitar pedals labeled as "stompboxes," but that is the last time you will see that uncultured term here.
If you are familiar with audio effects, you will already know what each of these pedals "do," essentially. But beyond simply what each effect does, I will do my best to explain how these were crafted with guitars in mind. And further, the advantages and pitfalls of using such gear with different equipment.
Below, I've done my best to categorize effects into applicable "families." But please be aware that the method, nature, and even sound of the effects can vary greatly within these groups.
Long before pedals, there was the guitar amplifier. And before those amps had separate "gain" and "level" controls, overdrive was a natural occurring phenomenon when cranking the volume. As with most unintended qualities, this was rejected at first, and embraced later. What happens is the peaks of the amplitude in the signal get "clipped" or blocked off, unable to surpass a certain threshold. This alters the shape of the waveform and, therefore, changes its timbre.
Eventually, amplifiers would be developed into having both pre-amp gain and powered amp level. But by this time, the overdriven sound had become a staple to basically every genre that utilized the electric guitar. Thus, guitarists wanted more overdrive options, and pedals were crafted to provide them!
Notes on Headroom
Headroom, in the context of pedals, will refer to how great of amplitude or level can pass through the circuit before clipping begins. If you do much audio work in the digital realm, you may be familiar with clipping being those nasty popping sounds that stick out of your mix, a result of how the digital audio is being processed. But for analog drive, both intentional and unintentional, there is usually a much smoother and reined in distortion (soft clipping, if you will).
The point being is that when you turn up the "gain" on your overdrive pedal, this creates intentional
overdrive. But if your signal is too loud going into the circuit, there will be unintentional
clipping. Your overdrive circuit was specifically designed to give a smooth, natural, and creamy driven sound. Surpassing the allotted headroom, however, was not.
Thus, always be mindful of how much volume level you are sending through your pedals. While applicable to all units, I mention this now as it is most important for drive type units. They will most frequently have headroom that is not ready for line level signals. In this context, if you find you are getting more drive than you expect, turn down your volume.
And after that extensive lead in, we finally arrive at the Overdrive. The controls you will find on the typical Overdrive are generally: Gain/Drive, Tone, and Volume/Level. Gain will increase the amount of overdrive in your signal. The Tone knob may be less familiar if you are coming from a non-electric guitar environment. It is simply a very simple EQ shaper for the sound. Low is more bassy, while high possesses more treble content. Some tone controls can boost basses or highs, while others can simply cut one side of the signal. You may encounter Overdrives with more complex EQ, perhaps a knob for both low and high, but a full 3 band EQ on a drive is exceptionally rare. Your Volume knob is also self explanatory, it controls the level of the signal that is leaving the pedal.
Metal mania! It is now time for Distortion! The controls you will often find on a Distortion pedal should be similar to that of the Overdrive. What most tend to be confused about, though, is how they are different. The quickest way to explain it is that a Distortion pedal will simply be capable of more
distortion than the Overdrive. This may be a simple enough description, but the philosophies between the two can have a stark contrast. You see, as the general guiding principle, Overdrive pedals are meant to behave like the overdrive that occurs naturally in amplifiers. Guitarists will often speak of a drive pedal being "dynamic." What they mean by this is that more drive occurs when slamming the guitar hard than when playing it softly. This gives players more natural and organic sound qualities for their guitars. Distortions, on the other hand, are typically NOT meant to be dynamic, but to give a constant level of distortion throughout the signal.
To this end, the majority of your electronic gear will see more consistent results when using Distortion as opposed to Overdrive. But, as always, don't let this dissuade you from giving Overdrive pedals a try.
Splaaaaat! Things are about to get fuzzy.
The Fuzz pedal was one of the first guitar effects around, and it existed to essentially mimic faulty equipment. As the 60s rolled around, amplifier technology was still relatively simple, and players were beginning to actively try to get grittier and dirtier sounds.
You will find the same drive controls here as the previous pedals, but the gain may more typically be called "fuzz" or something cheeky. The two most important things for you to know about Fuzz is that the clipping is very hard, and the circuits incredibly sensitive to input levels. For guitarists, this means they can go from a sludgy wall of destruction to mid-life crisis blues picking with a simple turn of the volume knob on their guitar. For our interests, however, you may find it difficult to put an electronic instrument through a Fuzz without it turning into a garbled mess. So unless a noisy nightmare is desired (which it sometimes is), to best use a Fuzz pedal out of the context of an electric guitar some type of re-amplification should typically be employed. If not, just be sure your volume levels are about as quiet as you can make them.
Notes on Stacking
While we will briefly discuss using pedals together later, special attention should be given to the use of multiple drives. Stacking drives is a "thing," as it were, so you should pay close attention to the ramifications. Note that as the amplifier of a guitarist usually has some manner of overdrive occurring, just one drive pedal in their signal chain will essentially result in gain stacking.
Unfortunately, there is no easy answer for the best way to line up multiple drives in your signal chain. A Distortion going into an Overdrive may create a muddy mess of signal, while an Overdrive going into a Distortion might sap away all the character of the overdrive. The best advice I can give you is that for your pedals to behave as "normal," have the units with higher headroom towards the end of your signal chain. Just remember that desirable effects can be found in the realm outside of normal, and that experimentation will be required.
Modulation is a term that sees a great amount of use in the musical world. From being the standard term for a key change to the humble modulation wheel on your keyboard. But for the purpose of this article, I will use the word to describe effects that posses a constant motion (modulation) or sweep in their audio processing. Without the sweep, the signal may still be altered, but it is that constant motion that is integral to the sound of these effects.
As there is a sweep present for these effects, they shall posses two specific controls for you to be aware of. These are the Rate and the Depth. Your Rate will control the speed of the sweeping modulation, while the Depth will increase or decrease the intensity or prominence of the effect.
Vibrato and Tremolo
Many of you may already be familiar with the terms "vibrato" and "tremolo," the former is a sweeping of pitch, and the latter a sweep of volume. However, in the world of guitars, these names can be turned on their heads. There were early guitar amps that had tremolo type effects built in, but named them vibrato. And to this day, you may come into contact with Vibrato pedals that actually perform a tremolo type effect.
It should also be mentioned that there are Tremolo pedals that do not sweep the volume, but apply filter or EQ of the signal. These can sometimes be more appropriately described as Harmonic Tremolos. Still other Tremolo pedals even seek to recreate a rotating speaker effect.
Thus, it becomes difficult to explicitly state the behavior of these effects when they can oft be named so incorrectly. I am therefore left with to be giving you the uninspiring advice of "listen to what it does and decide for yourself." Maybe slightly better advice would be to exercise extreme prudence before making a purchase in this specific family of pedals.
Totally 80s! There was a period of time that every guitar in recorded music was slathered in chorus, before it fell out of favor for a decade or two. What Chorus does is mix the input signal with a slightly delayed and pitch modulated (real vibrato) altercation of that signal. This creates a "phasing" effect between the two signals which is the crux of all our modulation type effects here.
If you are not familiar with what characterizes a phased sound, I will offer a visual representation. If you are in your car waiting to make a turn with your turn signal on, and there is a car ahead of you with their turn signal on as well, watch the two blinking lights. Chances are the timing on these blinks is not identical. Watch how your light slowly synchronizes with the other, they are seemingly blinking in unison, then they fall out of rhythm. They match so well and then are completely different; this is what is happening with a phased audio signal!
Of course, the chorus effect's name comes from a human choir (chorus). Having a group of people sing, their pitches and timing can never be perfect. This creates a huge and lush sound of natural phasing that is really rather poorly replicated by just the two signals involved with our Chorus pedals. However, the "artificial" nature of this effect is what gives it its character in the first place.
On quick note, some Chorus pedals may be able to provide a completely wet (effected only) signal. These will typically be referred to as a Vibrato Chorus (real vibrato).
A touch more direct than the naming of Chorus devices, Phasers or Phase Shifters wear their modulation heart on their sleeve. How it goes about with the phasing of your sound, however, is somewhat different.
A Phaser uses a series of all-pass filters to alter the phase of your modulated signal. This creates little peaks in your frequency spectrum that are swept back and forth as per this family of pedals. How many filters are used in this signal chain will be referred to as "stages" in the description of your device (4 stage Phaser, 8 stage Phaser, ect...) and you may have the ability to adjust how many stages the effect uses. Basically, the more stages, the more pronounced the effect.
Generally speaking, the character of a Phaser will be a tad more artificial than that of a Chorus. But the real difference you will find between these two effects is the shape of the modulation waveform. Typically, your Chorus pedals will only posses sine wave or triangle wave shaped modulation, a simple up and down motion. Phasers, on the other hand, usually have much more waveform options. Sawtooth, ramp, and S+H type modulation is vastly more prevalent among Phasers. If you find yourself wanting a "synthier" type of modulation effect, Phasers are the way to go.
From literal to more obtuse, now we come across the Flanger. The Flanger works much like a Chorus in that it delays a signal input and then mixes dry and wet together, modulating the speed (and thus, pitch) of the wet signal as it goes. In practice, you will find the delay times on Flangers to be much smaller than that of their Chorus cousins. The origin of the term comes from the original method of creating the effect where the "wet" signal was a tape reel being manually slowed down by touching the flange (side) of that moving device.
What truly separates Flangers from the Chorus is that Flangers typically incorporate feedback for their modulated signal. This feedback can get very intense, creating a significantly resonant whistling.
As to Phasers, the harmonic content of the phasing effect is much smoother in that of Flangers, but you will generally find less exotic waveshapes for the modulation.
So, to briefly summarize our modulation effects: Chorus will be the most subtle, Flanging will produce the most intense phasing with their heavy feedback, and Phasers will posses the most exotic and unnatural sounds.
Signal morphers! What an elaborate term for this family of effects, but I found it to be the best blanket term for this wide variety of audio processing. The main difference between these effects and modulation type effects is that, while it is certainly possible that modulation may be integrated with one of these pedals, it is not a necessary component in how the effect works. The other major discrepancy instead of splitting the signal to alter and blend, these effects either directly alter the incoming signal, or use the incoming as a basis for generating additional signal content.
Ring Modulation is a clangy, metallic effect where your input signal is multiplied by an oscillator on-board the pedal. In the context of a traditional subtractive synthesizer, you might typically find ring mod being available between oscillators. For guitar pedals, however, you will find much less control over your multiplying frequency than with a synth. This is because you will almost never find the ability to changer the waveshape, and you will have no ability to adjust the frequency of the effect relative to your playing pitch beyond getting lucky with your manual settings.
In the guitar world, Ring Mod isn't typically popular. To that end, simple Ring Mod pedals can be hard to come by. They are more often very complex noise pedals, or a ring mod effect has been added on as a bonus to some other type of effect.
Very specific to electric guitars, the Wah pedal is more about the operating style than actual audio processing. The actual audio effect of the Wah-Wah is a simple filter, but the hardware of the Wah is a rocking footswitch that controls the filter's cutoff. This allows the player to slide the filter effect back and forth at their leisure; the sensation of the manually controlled filter sweep is what led to the onomatopoeic name of this effect.
While you may be perfectly capable of using this effect outside of the context of guitars, remember that these units are specifically designed for a player that is standing up. Operating a Wah by hand will be awkward, as the pivot on the lever is meant for both the weight of a player and the longer length of a foot.
Filters are a simple enough effect, they run the input signal through a filter. Just static filter pedals, however, are not the most common type of pedal. The above mentioned Wah pedal is significantly more likely to be used by guitarists. But while they technically do the exact same thing, the hardware design of the Wah is what makes it its own specific thing.
To reiterate, just a static filter is hard to come by. Filter effects are much more frequently designed as Envelope Filters. This means that the cutoff of the filter is moved by an envelope (a simple automation shape) which is triggered by spikes in the signal related to our guitarist's playing. These types of effects can sometimes be referred to as "auto-wah" pedals, and they certainly perform the moving filter cutoff style easier than having to manually control it.
Since Envelope Filters are balanced with guitar signals in mind, you will probably find them unwieldy to use outside of that context. Furthermore, guitar filters in general will be vastly more simple than dedicated synthesis filters.
Pitch Shifters will produce a signal that as an altered pitch of the input signal and send both to output. The most simple and numerous types of these effects will produce pitch shifts at the interval of an octave, either above or below the incoming signal. More complicated Pitch Shifters will allow the user to manually set the pitch of the effect.
Octave effects will require special note. While you may see standalone Octave pedals, more frequently it is an addition to a different type of effect. Most common being the Octave Fuzz.
Bit Crushers will digitally lower the bit depth or sample rate of their input signal. In the world of guitar pedals, these will typically either be very simple effects, or complicated noise devices for those who wish to experiment.
Synth pedals can encompass a wide variety of signal generating styles. Most simply, they will be generating a specific tone based on the input signal. In a way, Synth pedals are very much like the above mentioned Pitch Shifters. However, the guitar Synthesizer will offer you many more options in shaping the sound produced.
You will encounter different sorts of Synth pedals, both digital and analog, with and without filters, ect... But however they create the synthesized sounds, know taht a guitar signal is what the device has been balanced for. These devices may not function as expected when dealing with louder or more complicated signals.
Space and Time
When sound is produced in any "space," it collides and bounces off objects in much the same way light is reflected off everything you see. These effects seek to replicate this, repeating the input signal multiple times as if it were moving about in a real space. And as we draw out the space, the passage of time becomes more apparent; these individual echoes clearly becoming their own signal as opposed to ambiance.
Worth noting on these types of effects is there may be talk about "trails" available. This simply means that the duplicated signals will finish their decaying even if you click the pedal effect off before it is complete.
Reverb is probably the most common audio effect in any area of recorded music. For guitar pedals, Reverbs will most often function in the rackmount or software style with a variety of styles such as hall or plate. The second most common variety of Reverb pedals are specialist types of units seeking to be more unique than the standard studio fare.
Requiring specific mentioning, Spring Reverb will be the only traditional style of reverb you will find to have their own dedicated unit. For early amplifiers equipped with a reverb effect, they did this with an actual chamber of springs that the audio was processed through. It is because of this that guitarists, who can be dedicated to their amplifiers, might have specific desire for the spring sound. This explains why you can see dedicated spring style pedals, be they digital or actual analog spring units.
Lastly, the one reverb type you could find even more specific to guitars than Spring is Shimmer Reverb. These units simply add an Octave effect to some of the reverb to create an almost choir like effect.
Delay pedals duplicate the input signal in much the same way that Reverb pedals do. The big difference being that while reverbs produce a huge number of these duplications at quiet levels, the delays of the Delay are much louder and more pronounced. Additionally, the repeats of your Delay pedal may be capable of so much feedback as to create self oscillation. You may see Delay pedals referred to as Echo units, but there is no real difference between the nature of their repeats to differentiate the names.
One thing specific for the Delay effect in guitar pedals is that you will find a wide variety of both analog and digital type units. Early Delay pedals were analog because that was the technology available. The downside of these units being that each delay would add subsequent noise for each repeat. This was countered by filtering the repeats, creating a gradual tone roll-off as the delay decayed. As technology improved, digital Delays were able to offer clean repeats no matter how long they lasted, while also providing much longer repeat time. But guitarists would eventually come back around to desire the analog sound, and you will find a variety of Delays available in either style.
More exotic methods of delay have also become popular in the pedal format, taking what was traditionally not something that could be in a compact pedal and doing so either digitally or with downsized technology. The most prevalent of these being Tape Delay. Like our aforementioned Spring Reverb, Tape devices (neither compact or cheap at the time) have been used prominently by guitarists of old, and newer players desire that specific sound.
The ultimate Delay, the Looper allows the player to record an entire phrase or passage to play back at their leisure. The idea behind the Looper is to allow the solo performer or a small ensemble the ability to layer their own backing tracks, creating the illusion of there being more performers present.
These types of pedals adjust the level of their input signal in certain ways. Essentially, these will be mixing console tools paired down to the pedal format.
The Boost simply raises the volume of the input signal. The "clean" Boost altering the signal as little as possible, and the "dirty" Boost closer to a low gain Overdrive.
I suppose now is as good a time as any to teach you how electric guitars work! For "passive" or un-powered pickups, simple magnets and a coil of wire create a magnetic field that, when disrupted by vibrating metal strings, generates electricity! What this has to do with the Boost is simple: electric guitars can generate very small electrical signals. This means that even with the volume cranked, the guitarist may not have enough level to do what they want to do. This is what necessitates the Boost pedal!
For our purposes, however, the Boost will not have much use. Because a powered instrument has the ability to adjust its volume much more intensely and is, essentially, its own boost in this context. Therefore, it is in re-amplification situations that you may find the most use for a Boost pedal.
EQ or Graphic Equalizer pedals are able to either boost or cut certain frequencies of your signal. As we are working outside of the context of electric guitars, chances are you are using a mixing console (or mixing via software) with fully capable EQ manipulation capabilities. The one bonus you may find with a pedal, besides the compact form factor, is that they can posses 5 to 10 band equalization. Compare this to the typical mixer which only has 3 band EQ.
A very common audio processing tool, Compression lowers the maximum amplitude (headroom) of the signal. This makes the quieter areas of your signal louder in context. Compression pedals are obviously balanced with instrument level signals in mind. With a huge swath of compression tools available, you may find pedals not your ideal choice for this effect.
Amp Modelers seek to specifically replicate the sound of specific amplifiers. This takes into consideration both the pre-amp and speaker cabinet. You will find two major flavors regarding this type of pedal. Most Amp Modelers are digital effects that are capable of a huge variety of amplifier styles. These types of devices can sometimes be in a desktop module format rather than the compact pedal form we have been discussing.
More specialized, the other group of these pedals are analog devices that seek to recreate the pre-amp characteristics of single specific amplifiers (for convenience, or for the rarity of the amp in question) as closely as possible.
Besides all the effects we have now discussed, there are also Multi-effect units. These will be digital units that contain a huge swath of effect options. Obviously, the Multi-effect format is something you will find in devices other than pedals, but pedals will have a focus on the effects most frequented by guitarists. You may also find pedals that combine a few frequently paired effects (such as Delay with Reverb), but these generally won't be referred to as Multi-effects.
Be aware that quite a few of the effects we have discussed may come in "bass" variations. These are most typical with drive pedals, but you can find bass versions for all sorts of things. These exist because the frequencies output by electric bass guitars are obviously much lower than standard guitars, and circuits designed with standard electric guitars in mind can sometimes not provide the appropriate frequency response. It may seem to you that this would make the bass variations ideal for non-guitar use, but be wary. While these units are designed to maintain a full breadth of bass signals, the high frequency response is something that may be ignored.
One of the biggest challenges for pedal manufactures is how to fit a plethora of controls within the rather small pedal format. Luckily, there are a few creative ways to help squeeze a few extra controls in all that limited space.
Dip switches are tiny switches, much smaller than the typical toggle switch, that can be placed directly on the circuit board. You may find dip switches internally or (typically) on the back of your pedal housing.
Trim pots are tiny knobs you will find internally and probably need a small screwdriver to turn. Given the hassle of opening a pedal up, these will generally be set and forget controls such as overall output level or balance.
With digital control becoming more advanced and elaborate in the pedal world, we are also beginning to see knobs with alternate controls. A footswitch will be your typical activator for such alternate controls.
You may also find pedals with an "exp" or expression input. The expression pedal is a rocking footswitch, much like a Wah pedal, that simply exists as an accessory control to whatever is manipulated by expression when it is available. Much like alternate controls, more complicated digitally controlled pedals may allow you to set a wide variety of different controls to your expression jack.
For modern modulation and delay units, it has become popular to include tap tempo. Tap tempo simply allows the player to set a tempo/BPM for a relevant parameter on their pedal via a dedicated footswitch.
Another new development in the world of pedals, we are starting to see more units with midi implementation. While you may be lucky enough to have a unit with automated control of parameters, midi is most typically only used for the saving of presets and setting tempo.
Power Supply and Using Multiple Units
While there are a few passive (non-powered) devices in the pedal format, the vast majority of these effects require electricity. Pedals frequently are able to be powered by battery, but will almost always posses a jack to be powered via AC adapter. Be aware that if you are powering multiple units in a chain with an adapter, you will have a higher chance of noise being introduced to your signal chain. There are specific "clean" power supplies available to avoid this, but having every unit powered by battery will work just as well.
Of special note in regards to power supplies, the vast majority of pedals are designed to run at 9 volts. However, there are some units that run at 18 volts and take either an 18 volt power supply exclusively or are variable and can run from 9 to 18. The benefit for guitarists is that drive pedals running at 18v will have more headroom. But special caution must be taken when in the presence of 18v power supplies. Using one with a pedal only designed to run at 9v will instantly fry it.
Thus, we come to the specifics in how to order your pedals when using multiple different types. Sadly, there is no definitive answer to this topic beyond your own personal preferences and the abilities of your effects. Simple logic just needs to be applied in how you wish to sound. If your Distortion is in front of your Delay, your distorted signal will be delayed. If your Delay is in front of your Distortion, all of your delays will be distorted. The only real guiding principle is that the very sensitive Fuzz circuits typically want as little going on in front of them as possible.
Voltage Starve and Sag
On the topic of power, pedals are unique in that they are so frequently battery powered. The thing about batteries, of course, is that they run out of charge and die. For pedals with analog circuits, the dying battery creates a gritty and sputtering sound frequently referred to as "sag." Beyond simply controls not working at peak efficiency, lower voltage will result in lower headroom. And as we've learned, lower head room means more drive.
Guitarists have found this to sometimes be a desirable state, especially in regards to fuzz. In fact, you may find more elaborate fuzzes with their own dedicated voltage starve control. And fancy power supplies may also give you the ability to starve the power output for you to experiment with sag to your heart's desire. However, be advised that this is specifically something to be used with analog circuits, digital effects will simply stop working correctly or at all without sufficient power.
Buffers and True Bypass
Two things related specifically to peals are the Buffer and true bypassing signals. The Buffer exists because when using multiple pedals or sending a signal through a long cord, clarity in the signal can be lost. You can find dedicated Buffer pedals, or other effect pedals that have the ability to buffer their output.
True bypassing is a feature you may find touted regarding a pedal's functions. When a signal runs through a pedal that is not true bypass, even when the pedal is "off," the signal is still passing through the effect circuit. If your pedal is capable of true bypass, it will have a separate signal path for when the pedal effect is off. Why this is desirable is that your signal can be altered when going through an effect circuit essentially set to zero, while the true bypass path should keep your signal the same as when it came in.
One huge thing in the world of pedals are newer units that are made to sound like, or straight up circuit clones of, older units. Since you can't have a copyright on a circuit, this is a practice that has gone on since even the early days of compact pedals. From DIY projects to large companies, a significant percentage of pedals are clones to some extent (this mostly concerns analog drive pedals as those circuits are the most simple and easiest to copy).
It's important to be aware of this practice because not all builders are as transparent about how cloned their pedals may be. Some are proudly declared to be part for part clones of famous older units. Others may cheekily allude to what their progenitors may be. But some may make no mention that they are straight up clones. The point being is that you don't want to get what you think are two different pedals, only for it to turn out that they are both clones of the same thing. Unless a builder proudly declares their pedal to be an "original circuit," just be aware you might be fancying a clone of something you already have.
Here are just a few commonly cloned pedals to be on the lookout for:
*Ibanez Tubescreamer - The defacto Overdrive pedal. If you see an Overdrive pedal referencing a mid hump, the color green, or 808 (not to be confused with the drum machine), you may have something Tubescreamer derived.
*Klon Centaur - Usually just called a Klon, the Centaur is another extremely popular Overdrive for cloning. If an Overdrive pedal proclaims to be "transparent, with the ability to be used as a clean boost," or has some manner of beast-man on its housing, you may have what is popularly referred to as a Klone.
*Proco Rat - The Rat is a Distortion pedal that has endured to this day almost unchanged since its introduction in the late 70s. If you find a Distortion pedal that declares it can sound like a Fuzz, or mentions rodents, you may have a Rat in the house.
*Electro-Harmonix Big Muff Pi - Arguably the most popular Fuzz pedal ever produced, the Big Muff family included a huge swath of different variations. Almost any Fuzz pedal you may come across with a full spectrum of sound and plenty of bass response is probably Big Muff derived.
*Dunlop Fuzz Face - One of the very first truly successful compact pedals, the simplicity of this circuit makes it a favorite of cloners and DIYers alike. Fuzz Face styled Fuzzes will will be much "splattier" and broken sounding with focus on higher frequencies when compared to Big Muff style fuzzes.
Parts and Manufacturing
Another phenomenon to be aware of is how certain parts or places of manufacture can inflate the value of pedals. You may find yourself confused to find what you assume are two of the exact same pedal, but at vastly different prices. Both certain components and place of manufacture can be quite prized in pedals that have remained in production for a long time. Both these factors create rarity, of course, with parts sometimes being completely out of production and regions of manufacturing simply not being used anymore.
Boss pedals are the clearest example as far as manufacturing goes, with units made in Japan usually viewed as the "best," but any unit that has seen different places of manufacture over its lifetime will usually have one region be the preferred one, warranted by performance or not. Components can be less clear and vary from device to device, but when you find a builder talking about specific parts used in a pedal, you better believe they think that's important.
Pedals really were modular for the everyman, providing compartmentalized effects that could be used with a variety of gear. But with the popularity of modular synthesis in the Eurorack format, now things have come full circle. Don't be surprised to see more elaborate pedals with CV and other connectivity for use with Eurorack. This has gone as far to even see straight Eurorack components such as oscillators or filters being produced in the pedal format!
One specific accessory for guitarists to think about in regards to their pedals is the pedal board. The pedal board is nothing more than a platform to hold a group of pedals that are intended to be used together. These can be as simple as a plank of wood or as complicated as a deluxe and elaborate multi-tiered folding unit. The point of the pedal board is for the touring guitarist to have something that can be easily transported from one venue to the next. Boards obviously aren't necessary, and certainly less so for non-guitarists, but they are typically kept in mind by pedal manufacturers. Things like size ("footprint" is usually the term in this context) and jack placement, both audio and power, can have a drastic effect on how many pedals you can squeeze into whatever available space you may have.
When buying units second hand, of specific note is velcro. Velcro is one of the most popular tools to keep pedals secured to a pedal board, but this means that velcro must be adhered to the bottom of the metal housing. Velcro is great for sitting on other velcro, obviously, but not so great for sitting on a table top or carpet or really any other surface. Be on the lookout for whether a used piece you'd like to purchase has been velcroed or not, or you may be left with a sticky mess to clean up.
Lastly, one very board specific accessory is the loop switcher. Not to be confused with Looper pedals, the loop switcher allows the user to set up multiple different signal chains between their pedals for quick and easy activation.
Pricing and Availability
The market for guitar pedals is absolutely huge, and it supports a large variety of different companies. Some of these are dedicated exclusively to pedal effects! Even very small operations, typically termed "boutique," can thrive and produce a variety of pedals. It can be very exciting looking at all the exotic varieties of effects, but try to not get carried away with your spending. Guitar effects cater to the guitarist market, and when "good" amps and guitars cost more than $1,000, the pricing frame of reference can end up being skewed. Pedals can, therefore, become much more pricey when comparing their effect abilities with a non-pedal devices performing the same function. Add upon that the propensity for smaller manufacturers to make limited edition units (both for artwork and functionality) and you can soon find yourself spending synthesizer levels of cash for just a few pedals.
To this point, further mention should be made for old or "vintage" units. The prices for vintage pedals can be truly astronomical relative to the simple circuits involved. How does this happen? Two major factors are at play (short version: supply and demand). Firstly, compact pedals are not devices meant to be kept around for a long time like more complex effect units. Very few older examples have survived into the 21st century. Second, guitarists can be obsessed with recreating the EXACT sound of specific artists or favorite records. And to get the exact sound, they need the exact same gear. But before you go dropping huge cash on a vintage unit, you should be well aware that the electronics used in these devices were not meant last long. Thinking of a vintage pedal as an "investment" probably isn't the best idea for something that is overdue for failure.
Hopefully I have prepped you for possible sticker shock as you take your first tentative steps into the world of pedals. With all that said however, by all means you should try to welcome a few pedals into your hardware family! You may even find them becoming integral to your setup, even if no guitars are involved.
Quick pedal history in a handy infographic
Early pedals and their usage on hit songs
Long running youtube series that both educates on specific effects and showcases new models