I have several effects pedals for my guitar that have come out of storage and are now happy to be used by Zach. I also got to blow the dust off the Marshall and light that thing up again. What a beast.
In order to understand the sound of Rock & Roll you have to first know about how vacuum tube amplifiers work. Well, all amplifiers actually, but the tube amps have a special property that makes them particularly good for rock music.
In order to understand the sound of Rock & Roll you have to first know about how vacuum tube amplifiers work. Well, all amplifiers actually, but the tube amps have a special property that makes them particularly good for rock music.
It shouldn't be surprising that, just like rock and roll itself, the sound of rock came from blues music. In the late 40's many southern blues musicians came up from the delta, as well as places like Dallas and Atlanta, and settled in Chicago (Muddy Water, BB King) and Detroit (John Lee Hooker).
Early blues was often played at old plantation house parties and "juke joints" in the south, and its growing popularity meant that more and more people started to show up. Musicians had to play louder and louder so everyone could hear them. In the blues and jazz clubs of the north, the background noise exploded and suddenly an acoustic guitar and a loud voice just wasn't enough any more.
Early blues was often played at old plantation house parties and "juke joints" in the south, and its growing popularity meant that more and more people started to show up. Musicians had to play louder and louder so everyone could hear them. In the blues and jazz clubs of the north, the background noise exploded and suddenly an acoustic guitar and a loud voice just wasn't enough any more.
When amplifiers became available they delivered loudness, and this helped get the sound out to the back walls, but only to a point. When you turn the gain of an amplifier up, the output sound gets louder, but there is a point for all amps at which the signal amplitude becomes so high that the amp cannot process the full range of the signal and so it clips the tops and bottoms off the sound waves. This is a special form of harmonic distortion called, appropriately enough, "clipping". Here's a graphical depiction of clipping. The amplitude of the signal on the right exceeds the headroom of the amplifier and is clipped.
What at first seemed like a detriment ended up changing everything. Amplifier clipping, my friends, is nothing less than the sound of rock and roll.
The first inklings of the rock sound on a recording are from the late 40's.
Listen to the 1948 version of the John Lee Hooker song Boogie Chillin'. Which for all us white folk out there means "boogie children", with boogie being a type of blues that can also be a verb meaning to dance to such music. You can hear the power amp clipping severely in this song. It's rougher than 5'oclock shadow. But this sound immediately stirred up something emotional in people, because it's been a staple of guitar sounds ever since.
Which brings us to the two common types of clipping that guitar amps can produce and the reason why vacuum tube amp designs are one of the last holdouts from the onslaught of solid state design.
A typical amplifier must take a line-level (very low) signal and amplify it by several orders of magnitude. For various reasons, this huge amount of signal amplification cannot be accomplished in a single stage. So amps are broken up into two general stages:
- The preamp section, which does noise filtering and prepares the signal for further amplification
- The power amp section, which takes the output of the preamp as its input and amplifies it to full volume.
Each of these sections is often comprised of a chain of amplifier stages. For instance, the Marshall JVM head has a four-stage preamp and a four-stage power amp.
Why does this matter? Because an amplifier can be clipped at the input of any stage. Clipping that occurs in the preamp has a very different sound than power-amp clipping. Generally, the more stages an amp has, the more possibility for clipping exists somewhere along the signal chain.
If you know what to listen for, you can tell the difference between pre- and power amp clipping instantly just by listening. Preamp clipping sounds very bright and "fuzzy", or "fine-grained" to my ear, while power amp clipping is more "chunky" and "dirty" sounding. I'll give you examples but know that often guitarists will use both types at once.
Power amp clipping is what most early rock songs, stretching into the 1970's primarily used. Most amps back then did not have as many preamp gain stages (because preamp clipping was not on the minds of amp designers at hat time - avoiding it was). Power amp clipping requires you to either turn your amplifier gain way, way up (to 11:) or else use a speaker load simulator (also called a "Power Brake") to trick the power amp into thinking it's playing loudly...this is how studio recordings are made of power amp distortion since it's otherwise far too loud for the microphones (actually, it would clip the microphone, but that's another subject). Think of all those older chunky-sounding songs by the Beatles, Black Sabbath, Led Zeppelin, Hendrix, AC/DC, and Cream. That's primarily power amp distortion.
Then, sometime in the 1970's, amplifier shops in L.A. started modifying Marshall (and other brands) tube amps to add an extra gain stage in the preamp. This was major surgery on the amp, but there were by that time many very good amp techs out there. The first guitarist to really popularize the super-fuzzy preamp distortion sound was Eddie Van Halen, in what came to be known as the Van Halen "Brown Sound" (because it sounds a little "burnt"). It's a much finer-grained distortion, both warmer and fuzzier than power amp clipping produces.
This sound became so popular that by the 80's Marshall was making all their tube amps with four preamp stages from the factory. Now some of them, the like top-of-the-line JVM series, have five.
A word about sound quality. The reason vacuum tune amps are still with us and going strong in 2011 is because the vacuum tube by its nature clips much differently than a solid state circuit. Solid state amps clip very rudely, with a glassy, harsh sound. They also transition to this clipped sound more quickly. A vacuum tube on the other hand slowly settles into layers of warm, soft, round distortion, tones that even respond to the aggressiveness of the guitarists playing style - play with a lighter touch and the distortion rolls off like a wave, play harder and it comes back in a smooth gradient.
As you can imagine, amp designers have been trying to duplicate this behavior in solid state for decades. And they are getting much better. Not quite there but maybe 80%. One thing they have found is that while preamp distortion is vastly different between tubes and solid state, power amp clipping is not quite as distinct. For this reason many amp manufacturers make amps with tube preamps and solid state power amps. Marshall's versions are called "Valve-State" (the Brits call vacuum tubes "valves").
Another way to get vacuum tube preamp clipping is by using an effects pedal. There are pedals on the market that have tiny vacuum tube preamps built into them, and when you run your guitar signal through them they pass the already-clipped signal to your amps input stage. It's sort of like adding a pre-preamp. The best of these - the "Super-Overdrive" series, are made by Roland under the name "Boss".
So.
Because this blog post is not long enough yet, and because I titled it "Effected" and spoke of pedals, I might as well tell you about some other effects you can plug your guitar into. Not all of them, there are many, many floating around. Just mine:
Digital Delay. I wrote a rather long-winded post about reverb and then mentioned this at the end. Digital delay is a much more flexible implementation of delay, where you can vary the delay, repeats, fade out, etc to get about any crazy echo or delay effect you want. I won't go into all that but I wanted to mention The Edge. The Edge is the name of the guitarist for U2. No, that's not his real name. Anyhow, he is known for probably taking the delay sound further than any other rock guitarist. In fact The Edge uses delay as a solid part of his melodic structures. He is often only playing every other or every fourth note that you hear on U2 songs, the others being filled in by the delay system.
Examples: Most U2 songs, if you want to hear it plain as day, listen to the opening few bars of "Pride in the Name of Love". The U2 sound also heavily relies on Chorus effects.
Flanger. This is one of a huge family of sliding filters that include Wah pedals, Phasers, and Chorus effects. The flanger has a sweeping sort of mild phase-shifting sound. It's one of those things you have to use judisciously because it can become obvious.
Examples: Listen to one of my all-time favorite songs, Barracuda by Heart. The flanger is on the main guitar sound throughout the song. You can hear the filter sweeping up and down as it changes frequencies. Listen especially to the shimmering harmonics and the second guitar solo where it's dialed up. In my personal opinion, Barracuda has one of the best guitar sounds I've ever heard in a song. And I love those low dissonant chords right when she sings "I bet you're gonna ambush me" and "you better make up something quick". Awesome.
Super Overdrive. This is a pre-amp disortion pedal that sounds fuzzy, but more coarse than the Brown Sound, more vintage. Tell you the truth, I have a vaccum tube amp which does this effect nautrally, and better, so I really don't get anything new from this except a different tone.
Examples: Funk #49 by the James Gang.
Heavy Metal. This is not the sound of classic metal like Judas Preist. That is typically straight power amp distortion, a fairly rough sound. No, this is a very different form - think Metallica or Megadeth. It is not just distortion either, it also contains a potent dose of re-equalization. That's because the modern "Speed Metal" sound is not just acheived through distortion - it's signature sound is a super-smooth preamp distortion combined with a radical "scooped mids" EQ. In fact this is sometimes called the "scooped mids" sound. The term means that the majority of the mid tones are filtered out, with the resulting EQ profile resembling a scoop. This sound is all bottom- and top-end, with very little sound content in the mid-range. That's why no matter how loud you play the guitar, you can clearly hear the singer - the human voice falls within the frequencies that are filtered out of the guitar sound.
Examples: Symphony of Destruction by Megadeth. For Whom the Bell Tolls by Metallica.
Compressor/Sustainer. This one is harder to explain. It's called a compressor but I'll bet most guitarists don't have a clue about what it compresses. It compresses the dynamic range of the guitar sound. Dynamic range is the difference in volume between the loudest sound that can be reproduced and the quietest. So what effect does it have? Well I can tell you but you will need to listen to the examples to hear for yourselves. Dynamic range compression makes the loudest sounds quieter and the quietest sounds louder. The net effect is an apparent increase in volume as the tones are pushed towards the center. I say apparent because there is no real volume increase, our human hearing is non-linear and this just pushes more of the sound into our hearing range. But the effect is not about volume. In fact you usually set the pedal volume down so that there is no apparent volume increase. The real beauty of this pedal is that it will keep your volume constant even if you hit a string too hard or soft. This is especially important when playing clean. I'll bet there isn't a guitarist out there that does not compress their clean sound, if for no other reason than this mistake-cleansing property. Compression also tends to add a shimmering, glassy tone and increases the sustain of your guitar - that's because it's pushing quiet sounds louder, remember? As the sound fades, the compressor adds volume to it. If it goes too high, it will lower the volume to keep it in the center. For this reason a compressor is often called a "sustainer".
Examples: To hear a great example of a compressed clean sound listen to the intro to "Under the Bridge" by the Red Hot Chili Peppers. To hear the Rockman Sustainer, which is a different design of the same principle and was invented by Boston guitarist/MIT engineer Tom Scholz, listen to Long Time by Boston.
Whew. Ok, I'm done. Besides, you've got some listening to do.
Listen to the 1948 version of the John Lee Hooker song Boogie Chillin'. Which for all us white folk out there means "boogie children", with boogie being a type of blues that can also be a verb meaning to dance to such music. You can hear the power amp clipping severely in this song. It's rougher than 5'oclock shadow. But this sound immediately stirred up something emotional in people, because it's been a staple of guitar sounds ever since.
Which brings us to the two common types of clipping that guitar amps can produce and the reason why vacuum tube amp designs are one of the last holdouts from the onslaught of solid state design.
A typical amplifier must take a line-level (very low) signal and amplify it by several orders of magnitude. For various reasons, this huge amount of signal amplification cannot be accomplished in a single stage. So amps are broken up into two general stages:
- The preamp section, which does noise filtering and prepares the signal for further amplification
- The power amp section, which takes the output of the preamp as its input and amplifies it to full volume.
Each of these sections is often comprised of a chain of amplifier stages. For instance, the Marshall JVM head has a four-stage preamp and a four-stage power amp.
Why does this matter? Because an amplifier can be clipped at the input of any stage. Clipping that occurs in the preamp has a very different sound than power-amp clipping. Generally, the more stages an amp has, the more possibility for clipping exists somewhere along the signal chain.
If you know what to listen for, you can tell the difference between pre- and power amp clipping instantly just by listening. Preamp clipping sounds very bright and "fuzzy", or "fine-grained" to my ear, while power amp clipping is more "chunky" and "dirty" sounding. I'll give you examples but know that often guitarists will use both types at once.
Power amp clipping is what most early rock songs, stretching into the 1970's primarily used. Most amps back then did not have as many preamp gain stages (because preamp clipping was not on the minds of amp designers at hat time - avoiding it was). Power amp clipping requires you to either turn your amplifier gain way, way up (to 11:) or else use a speaker load simulator (also called a "Power Brake") to trick the power amp into thinking it's playing loudly...this is how studio recordings are made of power amp distortion since it's otherwise far too loud for the microphones (actually, it would clip the microphone, but that's another subject). Think of all those older chunky-sounding songs by the Beatles, Black Sabbath, Led Zeppelin, Hendrix, AC/DC, and Cream. That's primarily power amp distortion.
Then, sometime in the 1970's, amplifier shops in L.A. started modifying Marshall (and other brands) tube amps to add an extra gain stage in the preamp. This was major surgery on the amp, but there were by that time many very good amp techs out there. The first guitarist to really popularize the super-fuzzy preamp distortion sound was Eddie Van Halen, in what came to be known as the Van Halen "Brown Sound" (because it sounds a little "burnt"). It's a much finer-grained distortion, both warmer and fuzzier than power amp clipping produces.
This sound became so popular that by the 80's Marshall was making all their tube amps with four preamp stages from the factory. Now some of them, the like top-of-the-line JVM series, have five.
A word about sound quality. The reason vacuum tune amps are still with us and going strong in 2011 is because the vacuum tube by its nature clips much differently than a solid state circuit. Solid state amps clip very rudely, with a glassy, harsh sound. They also transition to this clipped sound more quickly. A vacuum tube on the other hand slowly settles into layers of warm, soft, round distortion, tones that even respond to the aggressiveness of the guitarists playing style - play with a lighter touch and the distortion rolls off like a wave, play harder and it comes back in a smooth gradient.
As you can imagine, amp designers have been trying to duplicate this behavior in solid state for decades. And they are getting much better. Not quite there but maybe 80%. One thing they have found is that while preamp distortion is vastly different between tubes and solid state, power amp clipping is not quite as distinct. For this reason many amp manufacturers make amps with tube preamps and solid state power amps. Marshall's versions are called "Valve-State" (the Brits call vacuum tubes "valves").
Another way to get vacuum tube preamp clipping is by using an effects pedal. There are pedals on the market that have tiny vacuum tube preamps built into them, and when you run your guitar signal through them they pass the already-clipped signal to your amps input stage. It's sort of like adding a pre-preamp. The best of these - the "Super-Overdrive" series, are made by Roland under the name "Boss".
So.
Because this blog post is not long enough yet, and because I titled it "Effected" and spoke of pedals, I might as well tell you about some other effects you can plug your guitar into. Not all of them, there are many, many floating around. Just mine:
Digital Delay. I wrote a rather long-winded post about reverb and then mentioned this at the end. Digital delay is a much more flexible implementation of delay, where you can vary the delay, repeats, fade out, etc to get about any crazy echo or delay effect you want. I won't go into all that but I wanted to mention The Edge. The Edge is the name of the guitarist for U2. No, that's not his real name. Anyhow, he is known for probably taking the delay sound further than any other rock guitarist. In fact The Edge uses delay as a solid part of his melodic structures. He is often only playing every other or every fourth note that you hear on U2 songs, the others being filled in by the delay system.
Examples: Most U2 songs, if you want to hear it plain as day, listen to the opening few bars of "Pride in the Name of Love". The U2 sound also heavily relies on Chorus effects.
Flanger. This is one of a huge family of sliding filters that include Wah pedals, Phasers, and Chorus effects. The flanger has a sweeping sort of mild phase-shifting sound. It's one of those things you have to use judisciously because it can become obvious.
Examples: Listen to one of my all-time favorite songs, Barracuda by Heart. The flanger is on the main guitar sound throughout the song. You can hear the filter sweeping up and down as it changes frequencies. Listen especially to the shimmering harmonics and the second guitar solo where it's dialed up. In my personal opinion, Barracuda has one of the best guitar sounds I've ever heard in a song. And I love those low dissonant chords right when she sings "I bet you're gonna ambush me" and "you better make up something quick". Awesome.
Super Overdrive. This is a pre-amp disortion pedal that sounds fuzzy, but more coarse than the Brown Sound, more vintage. Tell you the truth, I have a vaccum tube amp which does this effect nautrally, and better, so I really don't get anything new from this except a different tone.
Examples: Funk #49 by the James Gang.
Heavy Metal. This is not the sound of classic metal like Judas Preist. That is typically straight power amp distortion, a fairly rough sound. No, this is a very different form - think Metallica or Megadeth. It is not just distortion either, it also contains a potent dose of re-equalization. That's because the modern "Speed Metal" sound is not just acheived through distortion - it's signature sound is a super-smooth preamp distortion combined with a radical "scooped mids" EQ. In fact this is sometimes called the "scooped mids" sound. The term means that the majority of the mid tones are filtered out, with the resulting EQ profile resembling a scoop. This sound is all bottom- and top-end, with very little sound content in the mid-range. That's why no matter how loud you play the guitar, you can clearly hear the singer - the human voice falls within the frequencies that are filtered out of the guitar sound.
Examples: Symphony of Destruction by Megadeth. For Whom the Bell Tolls by Metallica.
Compressor/Sustainer. This one is harder to explain. It's called a compressor but I'll bet most guitarists don't have a clue about what it compresses. It compresses the dynamic range of the guitar sound. Dynamic range is the difference in volume between the loudest sound that can be reproduced and the quietest. So what effect does it have? Well I can tell you but you will need to listen to the examples to hear for yourselves. Dynamic range compression makes the loudest sounds quieter and the quietest sounds louder. The net effect is an apparent increase in volume as the tones are pushed towards the center. I say apparent because there is no real volume increase, our human hearing is non-linear and this just pushes more of the sound into our hearing range. But the effect is not about volume. In fact you usually set the pedal volume down so that there is no apparent volume increase. The real beauty of this pedal is that it will keep your volume constant even if you hit a string too hard or soft. This is especially important when playing clean. I'll bet there isn't a guitarist out there that does not compress their clean sound, if for no other reason than this mistake-cleansing property. Compression also tends to add a shimmering, glassy tone and increases the sustain of your guitar - that's because it's pushing quiet sounds louder, remember? As the sound fades, the compressor adds volume to it. If it goes too high, it will lower the volume to keep it in the center. For this reason a compressor is often called a "sustainer".
Examples: To hear a great example of a compressed clean sound listen to the intro to "Under the Bridge" by the Red Hot Chili Peppers. To hear the Rockman Sustainer, which is a different design of the same principle and was invented by Boston guitarist/MIT engineer Tom Scholz, listen to Long Time by Boston.
Whew. Ok, I'm done. Besides, you've got some listening to do.
1 comment:
Seriously? TLDNR! However, you may have some heavy music fans out there who will read the whole post!
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