:Amplifier basics with overdrive and distortion explanation:

The first thing in understanding the difference is understanding exactly how an amplifier works. For the most part, I will assume that you are not a complete turd head and can understand basic concepts like “electricity” and “vibration” or even “current flow”. And if you don’t a quick Google search will net you a pretty good answer.

Back in the days when guitars were first introduced as a major instrumental piece of a band, they were considered almost antiquity. In the case of a band, the guitar would have often been drowned out unless it was mic’d. We are talking here of acoustic guitars (since there were no other kinds back then) that use a sound box to resonate and amplify the strength of the sound coming from the strings.

You can demonstrate the act of amplification by going into a very large auditorium or a large empty room that is more or less sealed. You’ll notice that every sound you make (if the room is big enough) will echo. The same will occur it big canyons or large open valleys and fields. Sounds waves naturally dissipate, but as they dissipate they spread out and become larger. Now the trick in amplification of sound is that in ideal conditions you want the larger sound waves to come back 100%. While this simply cannot happen due to many environmental conditions such as wood not bouncing 100% of all sound waves; this can, however, be used beneficially in the case of an acoustic guitar.

The process of implication in an acoustic guitar is as follows, for simplicity and continuity we are talking about your standard 14th fret body attached dove tail, default sound hole, six-string guitar; and we will be talking about the A string in particular.

:WAVES?:
When striking the A note on a guitar, the string will (because of tension and size) vibrate at or very close to 440 times per second. The measurement when it comes to sonic characteristics is called Hertz abbreviated by Hz. At 440 Hz, the A string will push air away from it at a rate of 440 complete Sine waves per second. Sound waves can only exist if their is a medium for travel (Can’t scream in space because theirs no air for the sound wave to travel on), and obviously we are talking about air in the case of a guitar (lol underwater power chords).

The sound waves traveling on the air go two places on an acoustic guitar, half of the sound waves simply go outwards away from you and your guitar. They may come back at one point, but again, if they are not returned to the listener in an amplified form they will never be heard from. Quite simply those waves aren’t going to be heard by anyone not standing directly in front of you. That being said, the waves going INWARDS into the sound hole enter the complex and enriching process we know as amplification. The sound waves will do many things inside of that guitar body, but the main thing they will do is bounce around like there’s NO tomorrow.

Inside the guitar there should be no other holes besides the sound hole on the front of the guitar. This is to prevent leakage of the sound waves. Back to that 440hz A wave coursing through the interior. As the waves dissipate and spread out (think ripple on water) they will find that they can no longer travel on forever. There are walls that they simply cannot go through, we call those sound walls or barriers. In this case the sides of the guitar will both A) Absorb some of the wave, but they will indeed B) Bounce the waves back but in a larger fashion.

These now amplified waves will have exactly the same Hz value (same amount of waves per second) but their amplitude will be much greater than before. The following picture is that of an un-amplified wave resonating at approximately 18 hz.

This picture shows the EXACT same wave that has gone through the process of amplification:

In comparison, you could say that the waves travel more up and down. Using basic comparison to a wave in the water, you could say that larger waves tend to be stronger and as such their ability to push objects increases. The same concept applies to sound waves. These stronger waves that push more air exert MORE pressure on our ear drums, our brain then converts that stronger pressure into “louder” volume.

That is the basic concept of acoustic amplification. It is more or less the same in most applications of basic amplification.

But acoustics have a limit. Because in order to get a MUCH stronger wave out of an acoustic guitar, you’d need to somehow make the sound box MUCH larger. This slowly becomes simply impossible, because you can make a guitar as large as you want; but who’s going to be able to play it?

The need for amplification beyond the basic means of what we considered possible slowly became apparent.

:YOU DID WHAT WITH MAGNETS?:
In the 30’s micro phonic technology had already existed. The application towards picking up on guitar sound was efficient, but the microphones would have most likely had some effect on the overall tonal quality’s of the sound being produced. And besides, guitarists never considered themselves to carry around loads of equipment where ever they went. They were used to playing for small venues that mostly had some sort of microphone situation going on if it was REALLY needed in the first place. However, venues were slowly increasing and as such, the need for some sort of non micro phonic amplification technique was needed.

One of the earliest innovators was Lloyd Loar, an engineer at Gibson Guitar Company. In 1924, Loar developed an electric pickup for the viola and the string bass. In this pickup design, there was a magnet wrapped around a single copper coil. However, the signal produced by this method was very weak; as this method tried to pickup on the sound waves that were being passed from the string to the pickup.

However, a MUCH more efficient method that used the actually string vibrations was invented soon later in the 30’s. This method, as opposed to the Loar method, relied almost 100% on the vibration of the strings. Its a tad complicated so lets refer back to that A note.

Well, its still ringing at 440hz per second, which means that it is VIBRATING at a rate of 440hz per second. After all, that wave can only exist for how ever long its source is continually exerting force on the medium (again in this case air) around it. But, for a second lets remove the wave from the equation, lets play guitar in outer space for a second.

Since there is no medium for the strings to exert force on, there can be no sound. However, there can still be vibration of the strings. And, if you could somehow represent those vibrations, would you not have a representation of the sound wave? Well the answer is a definite yes. Well… what can you use in space and on earth that can represent waves? Well water wouldn’t help much, and we already know its a vacuum so that leaves air out of the equation. But we can use electricity! Yes, electricity follows down its circuit in the form of a wave. So the question remains, can electricity represent a sound wave? Well why not.

Inside todays modern pickups, there are anywhere between 6 to 20 something small magnets that are wound by copper wire. This copper wire, when electrified, has an effect on the magnets we call an “electro-magnetic field” in which it creates a field of magnetic strength beyond the magnets. This field can sense the vibration of the string because electric strings today are made of materials that can be magnetized.

In simple terms, as the strings vibrate, the magnets will “follow” so to speak the vibration of the strings. The magnets in turn then affect the signal passing through the copper wire and replicate the vibration of the string in electrical waves. If you were to be able to look inside the wire leading out of a guitar as a 440 A note was being strummed, AND you were somehow able to take a snap shot of the amount of complete waves passing the wire at a given point over the course of a second, you would see 440 little waves coursing through the wire.

I know that sounds complicated, but its really not that crazy if you simply understand that the wire is now the medium the wave is traveling on and the electricity going through it IS the force creating the waves. So what exactly do we do with these electric waves traveling down this wire?

:UP TO ELEVEN?:
Well several things can happen to this signal on its way to becoming sound waves. You could decrease certain aspects of the wave, offer resistance to certain parts of the sound wave and thus effecting the tone (tone pots anyone?) you could delay it, add effects, throw on a wah pedal and MANY other things. Electricity is MUCH more malleable than sound waves, you have almost COMPLETE control over how and where and when electricity goes ANYWHERE. We can use this power to a great extent.

But the one thing we are concerned with is the actual amp and what actually occurs inside that turns electric waves back into sound waves. Before you ask why would you want to do such a thing, think back to the acoustic guitar. With natural amplification, your ultimate limit is the size of the sound box you can create. With electricity and electric amplification, the ability to amplify the signal simply comes from your ability to increase its electric amplitude, which is still a pretty complicated process, but ultimately the tool it provides you will is worth the heavy price. It can basically be explained by this Spinal Tap quote:

Nigel: Well, it’s one louder, isn’t it? It’s not ten. You see,
most…most blokes, you know, will be playing at ten. You’re on ten
here…all the way up…all the way up….
Marty: Yeah….
Nigel: …all the way up. You’re on ten on your guitar…where can you go
from there? Where?
Marty: I don’t know….

Nigel: Nowhere. Exactly. What we do is if we need that extra…push over
the cliff…you know what we do?
Marty: Put it up to eleven.
Nigel: Eleven. Exactly. One louder.
Marty: Why don’t you just make ten louder and make ten be the top…
number…and make that a little louder?
Nigel: …these go to eleven.

Nigel basically sums up whats going on more or less. The ability to dial in the volume of YOUR preference is a INCREDIBLE tool in electric guitar playing. I’d be safe to say that most newer players don’t really understand that power to its full extent. even the smallest of amps can be amplified QUITE loud, but yet can still create sound at fairly low volumes.

Well how does this happen you ask? AND WHERE DOES MY BROOTAZ DISTORTION COME FROM? Not there yet my friend. Trust me, if you actually read and comprehend the entire thing I’ve written here I think that you’ll have a better understanding of electric guitar playing and what exactly makes it so DAMN awesome.

I don’t really want to go into the voltages and resistance and what not associated with tubes and current processing. And solid state amplification and distortion will come later.

:ACDC?:
Understand this, the guitar is fed an alternating current (AC) through the guitar cable, which then in turn goes around that coil, pickups any resonating frequencies (remember the magnets and the field!) which then will get affected by the tone and volume controls on the guitar. These affect the signal at its lowest signal value, and thus, will have TREMENDOUS effect on the overall sound produced by the amp. After the signal leaves the guitar it now holds waves that are replications of the vibration of the strings.

This new signal is still in alternating current form. In order for it to be usable for tube amplification, it will need to be transformed into Direct Current (DC). This is done by a transformer (a transformer transforms… what else did you think it would do?). Usually this is the smaller of the two transformers (usually two) since the actual amount of power the output of a guitar has is pretty small even with active electronics.

Once the current has been processed into direct current, it is fed into the preamp tubes. Preamp tubes are where your brootalz come from. Right there. Inside those tubes. There is an anode, a cathode, and a grid.

The cathode is the first part of the process, the tip of it is heated so much that the electrons literally BOIL off. Since they are negatively charged they are attracted by the positive polarity of the anode. But the electrons cannot simply go from one side of the tube to the other, why? Well because nothing is being done and the whole point of a tube is to increase the amplitude (strength) of the electricity. So how does that happen? Well, that grid. The grid is charged with a negative polarity. Why you ask? To give the electrons a hard time. This is to reduce and control the flow of electrons from the cathode to the anode. And in the case of guitar amplifiers, it simply allows someone to turn down the volume. But in reality, know that you are actually increasing the plate voltage and thus repealing MORE electrons.

:DISTORTION AND OVERDRIVE AHOY!:

Now the preamp tubes is where most modern guitarists get their sound characteristics made. This is where the grit comes from. Quite simply, there is a point where the tube just cannot allow any more electrons to flow through the plate. This isn’t a bad thing per say, but it does have an effect on the sound wave that the electrons are modeled after.

The waves will become clipped. And the relationship to how much clipping occurs is in direct proportion to the amount of current flowing through the tube. The more current past the threshold of a tube the sharper the clip. There are many ways to get a deeper clip on the sound wave, most noticeably is simply using more preamp tubes. This will cascade so to speak the amount of power from tube to tube.

For instance, starting at V1 (the first tube in a guitar amp, usually a preamp tube 12ax7) the power coming from the anode will be moderate, but it might not be that high. To the contrary, if your amp (like mine) has 6 preamp tubes in a row, the power flowing into the last preamp tube will be incredible and a VERY large clip will occur. If you do have a nice quality tube amp you can see this happening if you simply turn everything up. On one side you will see a VERY bright small tube glowing in electron flowing goodness. While on the other side you will see a tube that is bright but not THAT bright.

That is where preamp overdrive and distortion comes from.

After the current has passed through the the preamp section of the guitar amp it enters the power amp section. This is where the LARGER of the tubes you will see do their dirty work. These tubes are much larger and have heavy duty components in them that allow MUCH greater currents to pass through them while doing the same basic job. The power tube is what makes the guitar amp so to speak. Without it the preamp tubes would not have enough power to drive the speakers.

Power tube saturation and overdrive/distortion is also possible. But it occurs at MUCH higher current than preamp tubes.

After the current and the extremely pissed off electrons (they just got sent through like 12 tubes, how would you feel if that happened to you) need to vent somewhere and yell. Well, after they go through the last transformer they go directly into the speakers and push the driver back and forth replicating the waves they are flowing in.

Remember that A note? Well. After this whole process, of being amplified and resisted and pushed and pulled and heated, they resonate the speaker at a rate of 440hz. Replicating the original vibration of the string on the guitar.

:SOLID STATE/PEDAL OVERDRIVE?:

Quite simply, pedals and solid state distortion simply try their very best to replicate the natural occurring process that happens when a tube reaches its saturation point. Through means of transistors and switches, the cut the tops of the waves off. This results in a harsher and some would say less natural sounding overdrive.

That is by no means a bad thing if you want that sound. Artists such as Dimebag Darell used solid state amplification and distortion to get his signature chainsaw distortion sound. Which in all honesty is just as brutal sounding as it may ever get.

:OVERDRIVE OR DISTORTION?:

Basically they are terms that describe the severity of the clip that occurs in the wave. Overdrive is typically what occurs when a tube just barely reaches its saturation point. Soft clipping (the yellow wave) occurs and the sound becomes what I’d describe as “dirty”. This sound is lusted after by blues players who like to have their pick attack directly translated into how much dirt gets slapped onto the sound.

Distortion (red wave) can either be completely cut waves like in the picture or VERY severe overdrive curve, essentially a curve so sharp that it becomes almost flat.

That middle ground of having extreme natural overdrive is something that people spend thousands of dollars on. Getting natural distortion is just simply not that easy to get in a quality form. You will never hear me utter the phrase that its not worth it, because I would have no problem dropping 5k on a H&K triamp or a Ceriatone bassman reissue.