Guitar Amps
Guitar Amps
AMPS
DESCRIBING A GUITAR AMPLIFIER
A guitar amplifier (or amp) is an electronic device or system that strengthens the weak electrical signal from a pickup on an electric guitar, bass guitar, or acoustic guitar so that it can produce sound through one or more loudspeakers, which are typically housed in a wooden cabinet.
A guitar amplifier may be a standalone wood or metal cabinet that contains only the power amplifier (and preamplifier) circuits, requiring the use of a separate speaker cabinet–or it may be a "combo" amplifier, which contains both the amplifier and one or more speakers in a wooden cabinet.
There is a wide range of sizes and power ratings for guitar amplifiers, from small, lightweight "practice amplifiers" with a single 6" speaker, to heavy combo amps with four 10” or four 12" speakers and a powerful amplifier, which are loud enough to use in a nightclub or bar performance.
For electric guitar players, their choice of guitar amp and the settings they use on the amplifier are a key part of their signature tone or sound. Some guitar players are longtime users of a specific amp brand or model. Guitarists may also use external effects pedals to alter the sound of their tone before the signal reaches the amplifier.
THE STRUCTURE OF A GUITAR AMP
Typically, guitar amplifiers have two amplifying circuit stages and in addition frequently have tone-shaping electric circuits, which usually include at least bass and treble controls, which function similarly to the equivalent controls on a home hi-fi system. More expensive amplifiers typically have more controls for other frequency ranges, such as one or two "midrange" controls and a "presence" control for high frequencies. Some guitar amplifiers have a graphic equalizer, which uses vertical faders to control multiple frequency bands. Some more expensive bass amps have a parametric equalizer, which enables precise control of tone.
The first amplifier stage is a preamplifier. It amplifies the audio signal to a level that can drive the power stage. The preamplifier also changes the tone of the signal; high preamp settings add overdrive. The power amplifier produces a high current signal to drive a loudspeaker and produce sound.
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Various types of tone stages may affect the guitar signal:
Settings on the guitar itself (passive tone controls, active equalizer circuits in built-in preamps, pickup selector switch position, etc.)
Devices between the guitar and the preamp stage, such as a wah-wah pedal or other effects units, such as chorus or reverb.
Between the preamp and power stages (an effects loop or some dedicated amplifier tone circuits)
Between multiple stacked preamp stages (also called “gain stages”)
In feedback loops from a post-preamp signal to an earlier pre-preamp signal (as in the case of presence modifier circuits)
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Tone stages may also provide electronic effects—such as equalization, compression, distortion, chorus, or reverb.
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Amplifiers may use vacuum tubes (called valves in Britain), solid-state (transistor) devices, or both.
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The two common guitar amplifier configurations are: a combination ("combo") amplifier that includes an amplifier and one or more speakers in a single cabinet, and a standalone amplifier (often called a "head" or "amp head"), which passes the amplified signal via a speaker cable to one or more external speaker cabinets. A wide range of speaker configurations are available in guitar cabinets—from cabinets with a single speaker (e.g., 1×10" or 1×12") or multiple speakers (e.g., 2×10", 4×10" or 8x10").
https://en.wikipedia.org/wiki/Guitar_amplifier
THE 4 TYPES OF GUITAR AMPS
* The type of Amp you choose is a vitally important decision, as this will affect your price range, spec and overall tone. Let's scope each one in more detail:-
1. Vacuum Tube | Valve Amps:-
Valve amps were dominant in the music scene until the 1970's when solid state amps were introduced. Valve Amplifiers produce a warmer, more textured tone with a natural "overdrive|distortion" sound. They are also the loudest option even at lower power ratings. Valve amps are expensive to build and maintain & this is one of the main reasons that solid state amps became the more popular option amongst musicians.
Solid State Amps:-
Solid State amps are Cheaper, lighter, more reliable, reduced weight + heat and are less fragile compared to Tube amps, but still does not produce the same warm tone a Tube amp produces. Built in a similar way to tube amps, only using transistors instead. Some Jazz guitarists prefer the "cleaner" sound the solid state amps offer.
Hybrid Amps:-
Hybrid amps are a combination of tube & solid state amplification by using a valve preamp with a solid state power amplifier. This means the amp is more reliable and has a classic solid state high frequency response - popular with metal guitarists of the 80's & 90's like Dimebag Darrell, Gus G & Michael Amott; all whom used a hybrid amp at a point in their careers.
Modeling | Digital Amps:-
Modeling Amps incorporate Microprocessor technology which makes use of digital onboard effects in guitar amps that essentially produce different sounds & tones that simulate the sound & range of a variety of tube amps & different sized speaker cabinets. Many of these amps are programmable through a USB or home computer | laptop connection. The use of digital technology does give it a certain edge and because it's software dependant, you can upgrade instead of replacing new hardware.
COMBO VS STACK AMPLIFIERS
COMBO AMPLIFIERS
Originally Combo Amps were the only amps offered. They were designed to take up little space, and to easily transport for gigging purposes.
Some time later, the technology of amplifiers evolved and increased in power levels which encouraged the demand for a seperate head & cabinet.
Today combo amps have become more practise amps while vintage style amps are used for studio, touring or smaller events.
STACK AMPLIFIERS
A stack is made up of an amplifier head on top of a speaker cabinet.
* A head a top one speaker cabinet is referred to as a "Half Stack"
* A head a top two speaker cabinets is referred to as a "Full Stack"
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There is a vast variety of formats to stacks like the most commonly used being a lard head on 4x12" combo.
For smaller situations, there are options like the 2x12" or 1x12"speaker cabinets. An advantage to stacks is that it allows you the ability to mix up your amps & speakers based on tone & specs preference.
THE DIFFERENT CABINETS & THEIR CHARACTERISTICS
1x10" Cabinet
Used more in small gigs and studio work. Produces clean or crunch tones. Really doesn't produce much of a punch, but can handle a decent amount of gain depending on the speaker.
1x12" Cabinet
Mostly used for practise and studio work. Slightly larger than the 1x10" speaker, and thus produces more of the grit and low end punch that the 1x10" is lacking.
2x10" Cabinet
Best suited to clean and crunch tones rather than high gain, but gigging sized - clean & crunch amps can be used. They are normal sized speakers for Vintage style amps.
2x12" Cabinet
This is the most popular choice and most commonly used; and has become the industry standard format amongst musicians. They are designed to be easy to transport while still producing a big and powerful sound. This is fantastic for both live and studio situations.
4x10" Cabinet
Almost used entirely for live performing, these are the loudest of the 10" classic sounds. Not a common size, but can be found in vintage amps.
4x12" Cabinet
This is the big stage favourite and a Rockstar Standard! They are big and heavy, but produce unbeatable low response & power. Although they are used in Professional studio's, they sound their best on a large stage, and no doubt you would spot a couple of these on stage at a big stage event.
VOLUME | POWER | DISTORTION - IMPEDANCE + WATTS
Important: - Impedance and watts are words you'll hear often and it's because, these affect what speakers will work with your amplifier.
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Wattage is the power rating of your amplifier. This is how much is pushed through from the speaker. This is not to be confused with the volume rating, as this permits a separate purpose. Example is that some 15w's can sound louder than a 30w depending on volume ratings.
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TIPS TO KEEP IN MIND: -
* Cabinet wattage must = Amp wattage
* 50w amps or greater are best for large venue performance
* 40w amps or less are better for practise, studio and small-mid sized venues
Note: - Lower wattage tube amps allow tubes to 'saturate' & distort without having to turn the volume up too much.
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When it comes to Impedance, it's important to know & understand that input + output on the head and cabinet need & must match. i.e. If your cabinet has an 8 ohm input, then you need to make sure you use the mono 8 ohm output on the head.
It is of immense importance that you always buy a cab that matches impedance (ohms) and can handle at least what your amp is rated at in terms of wattage.
VOLUME
A variety of labels are used for level attenuation potentiometers (knobs) in a guitar amplifier and other guitar equipment. Electric guitars and basses have a volume control on the instrument that attenuates the signal from selected pickups. There may be two volume controls on an electric guitar or bass, wired in parallel to mix the signal levels from the neck and bridge pickups. Rolling back the guitar's volume control also changes the pickup's equalization or frequency response, which can provide pre-distortion equalization.
The simplest guitar amplifiers, such as some vintage amps and modern practice amps, have only a single volume control. Most have two volume controls: a first volume control called "preamplifier" or "gain" and a master volume control. The preamp or gain control works differently on different guitar amp designs. On an amp designed for acoustic guitar, turning up the preamp knob pre-amplifies the signal—but even at its maximum setting, the preamp control is unlikely to produce much overdrive.
However, with amps designed for electric guitarists playing blues, hard rock and heavy metal music, turning up the preamp or gain knob usually produces overdrive distortion. Some electric guitar amps have three controls in the volume section: pre-amplifier, distortion and master control. Turning up the preamp and distortion knobs in varying combinations can create a range of overdrive tones, from a gentle, warm growling overdrive suitable for a traditional blues show or a rockabilly band to the extreme distortion used in hardcore punk and death metal.
On some electric guitar amps, the "gain" knob is equivalent to the distortion control on a distortion pedal, and similarly may have a side-effect of changing the proportion of bass and treble sent to the next stage.
DISTORTION
Distortion is a feature available on many guitar amplifiers that is not typically found on keyboard or bass guitar amplifiers. Tube guitar amplifiers can produce distortion through pre-distortion equalization, preamp tube distortion, post-distortion EQ, power-tube distortion, tube rectifier compression, output transformer distortion, guitar speaker distortion, and guitar speaker and cabinet frequency response. Because many factors beyond preamp distortion contribute to a particular guitarist's sound, recording engineers and PA system techs typically put a microphone in front of the guitar speaker, rather than only use the guitar amp's pre-amp out signal. A sound engineer or music producer may send the DI out signal from the pickups to a separate track at the same time, so they can re-amp the signal later. In contrast, it is fairly common to use a DI box with electric bass.
Distortion sound or "texture" from guitar amplifiers is further shaped or processed through the frequency response and distortion factors in the microphones (their response, placement, and multi-microphone comb filtering effects), microphone preamps, mixer channel equalization, and compression. Additionally, the basic sound produced by the guitar amplifier can be changed and shaped by adding distortion and/or equalization effect pedals before the amp's input jack, in the effects loop just before the tube power amp, or after the power tubes.
POWER-TUBE DISTORTION
Power-tube distortion is required for amp sounds in some genres. In a standard master-volume guitar amp, as the amp's final or master volume is increased beyond the full power of the amplifier, power tube distortion is produced. The "power soak" approach places the attenuation between the power tubes and the guitar speaker. In the re-amped or "dummy load" approach, the tube power amp drives a mostly resistive dummy load while an additional low power amp drives the guitar speaker. In the isolation box approach, the guitar amplifier is used with a guitar speaker in a separate cabinet. A soundproofed isolation cabinet, isolation box, isolation booth, or isolation room can be used.
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https://en.wikipedia.org/wiki/Guitar_amplifier
AMP SPEAKERS
A guitar speaker is a loudspeaker – specifically the driver (transducer) part – designed for use in a combination guitar amplifier (in which a loudspeaker and an amplifier are installed in a wooden cabinet) of an electric guitar, or for use in a guitar speaker cabinet. Typically these drivers produce only the frequency range relevant to electric guitars, which is similar to a regular woofer type driver, which is approximately 75 Hz — 5 kHz, or for electric bass speakers, down to 41 Hz  for regular four-string basses or down to about 30 Hz for five-string instruments.
The cones of these drivers typically range in size from 6.5 in to 15 in with 10 and 12 in models being the most popular for electric guitar and electric bass combo amps and speaker cabinets. As with all loudspeaker drivers, the magnets are usually made from Alnico, ceramic, or, to reduce weight on more expensive models, neodymium.
Higher quality Alnico magnets are reserved for more expensive models. Well-known guitar speaker manufacturers include Jensen, Celestion, Eminence, Electro-Voice, JBL, Peavey, and Vox. Small practice amps often have 6.5  or 8  speakers. Combination (or "combo") amplifier cabinets often have one or more 10 and 12  speakers.
The largest speaker "stacks", used in stadium concerts, have eight 10 or 12 in speakers. Bass amplifier speaker cabinets for the bass guitar also often use one or more 10 or 12 in speakers (both 2x10 in and 4x10 in cabinets are popular; in addition, bass cabinets are more likely than electric guitar cabinets to use 15 in speakers.
https://en.wikipedia.org/wiki/Guitar_speaker
THE DIFFERENT AMP SPEAKERS & THEIR CHARACTERISTICS
Celestion Creamback
​The Celestion Creamback guitar speaker gives you classic British tone, with increased power handling for today's powerhouse amps. With its warmth and distinctive growl, the Creamback serves up the essence of British guitar tone, with low end grunt complementing its warm mids, crunchy upper-mids and sweet highs.
Celestion Greenback
The Celestion G12M Greenback 12" guitar speaker gives you classic British tone with a warm body and distinctive growl. The first Celestion speaker to feature a ceramic magnet structure, the G12M Greenback gives you a loud and assertive voice - perfect when paired with a powerhouse tube amp.
Celestion Vintage 30
​The Celestion Vintage 30 guitar speaker sounds amazing. Easily twice as loud as other speakers at the same power level, the Vintage 30 handles gargantuan overdrive with aplomb. Punchy lows, meaty mids, and a creamy, harmonically-rich high end make the Vintage 30 an excellent choice for your 4 x 12" cab, but it's also great in one- or two-twelve configurations.
Celestion G12T-75
Featured in the world's top selling 4x12 cabinet, the G12T-75 guitar speaker is a high powered rock player's dream. Built to meet the demands of high gain amplifiers, the G12T-75 combines a huge, tightly controlled low-end and aggressive mid-range with a softened top-end that adds a welcome sweetness to overdrive, distortion and aggressive upper harmonics.
Celestion Seventy 80
The Celestion Seventy 80 12" guitar speaker gives you modern British tone with gutsy midrange and plenty of top end punch. Characterized by its hefty bottom end, aggressive mids, crisp highs, and robust volume handling, this speaker sounds great no matter what style of music you play - and it's affordable!
Celestion Rocket 50
If you look in the back of any standard 4x12 cab, you will probably find a Rocket 50s placed - they're that popular! Characterized by its big bottom end, smooth mids, colorful highs, and healthy volume handling, this speaker sounds great no matter what style of music you play!
There is a variety of other speakers available, in a whole range of different sizes, styles & specs; some even made from interesting materials like hemp. The above is just a list of popular speakers for a basic understanding of variations.
The best way to truly find the sound you're looking for out for your amp speakers, is by testing them out - Trial & Error!
Also don't stress too much when it comes to changing speakers; Changing amp speakers is actually a pretty simple thing to do.
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CABINET CONSTRUCTION
Whether you're playing a combo or a roaring stack, the back of your amplifier contributes hugely to part of your overall tone. It's important to understand the different features offered by the two when making your selection.
OPEN BACK
The Open Back Amp's offer an open, non-directional sound with more ambience and great emphasis on high frequencies and less focused low end.
Combo amps usually have an open back, allowing space for the sound of the amp to 'escape'.
In Studio: - Open Back Amps are preferred because they offer more choice with potential mic placements.
On Stage: - Open Back Amps are fantastic for performers because they are able to hear themselves better. This is especially handy when there is no monitoring.
Some benefits to Open Back Amps is that they are Clearer and better heard, so there is no need to drive the amp up too loud to enjoy the tone. Because they are clearer, they can be heard better by all band members on stage too, especially with the drummer who would hear it coming through the front and back.
Some setbacks are that it is more challenging for sound engineers to control ambient sound, which may result in "spill" in the drum mics or other stage mics.
NOTE: - "Spill" (also known as bleed and leakage) is the occurrence in sound recording (particularly in close miking) and live sound mixing whereby sound is picked up by a microphone from a source other than that which is intended. Spill is usually seen as a problem, and various steps are taken to avoid it or reduce it. In some styles of music, such as orchestral music, jazz, and blues, it is more likely to be accepted or even seen as desirable.
CLOSED BACK
​Closed back Amps produce a directional sound through the front, projecting sound forward only. This generally produces a stronger Bass, midrange presence and tighter tone.
You would generally find closed backs on 4x12" quad cabinets and some combos.
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Some benefits to Closed Back Amps is that in Live & recording situations, Sound Engineers have far more control because the sound is captured and manipulated from a single main source. It also produces a powerful & defined type of sound.
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Some setbacks are that it doesn't compare with an open-back's natural ambience. Closed Backs also have a tendency of shooting a "laser beam" sound forward. This can also completely change by stepping left or right.
TOP 6 GUITAR AMP MANUFACTURERS
1.
Marshall Amplification is an English company that designs and manufactures music amplifiers, speaker cabinets, brands personal headphones and earphones, and, having acquired Natal Drums, drums and bongos. It was founded by drum shop owner and drummer Jim Marshall, and is now based in Bletchley, Milton Keynes, Buckinghamshire.
2.
Ernie Ball did not create anything new — he simply saw a demand and improved upon existing products and found ways to better fulfill market demands. By the early 1970s he took the company global by establishing distributors in Europe and Asia. Jimi Hendrix, Eric Clapton, Pete Townshend, and other rock icons were stringing up Slinkys, a trend that continues into the present, making Ernie Ball the second biggest string manufacturer in the country.
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Fender amplifiers have a long history. Leo Fender began building guitar amps before he started manufacturing guitars. The first of these amps were the K&F models, which were produced between 1945 and 1946. The original Fender amps were tube-powered and the company also started producing solid-state models in the late 1960s.
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DR Handmade Strings is a manufacturer of guitar and bass strings located in Westwood, New Jersey. DR Handmade Strings was founded in 1989 by Mark Dronge, son of Guild Guitars founder Alfred Dronge, and Dr. Benzion Rapoport. DR is an all American family owned business that is known for its hand craftsmanship and referred to in advertisements as "The Handmade String".
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Peavey Electronics Corporation is an American company that designs, develops, manufactures and markets professional audio equipment. It is one of the largest audio equipment manufacturers in the world, headquartered in Meridian, Mississippi.
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Line 6 is a manufacturer of digital modeling guitars, amplifiers (amplifier modeling) and related electronic equipment. he company was founded in 1996. Headquartered in Calabasas, California, the company imports its products primarily from China. Since December 2013, it has been a wholly owned subsidiary of Yamaha Corporation.
