Types
Paul Reed Smith Standard 22
Solid bodySolid body electric guitars have no hollow internal cavity to accommodate vibration and no sound holes such as those used to amplify string vibrations in acoustic guitars. Solid body instruments are generally made up of hardwood with a lacquer coating. The wood is dried for 3 to 6 months in heated storage before being cut to shape. The sound that is audible in music featuring electric guitars is produced by pickups on the guitar that convert the string vibrations into an electrical signal. The signal is then fed to an amplifier (or amp) and speaker.
One of the first solid body guitars was invented by Les Paul. Gibson did not present their 'Les Paul' guitar prototypes to the public, as they did not believe it would catch on. The first mass-produced solid-body guitar was Fender's Broadcaster (later to become the 'Telecaster') first made in 1948, five years after Les Paul made his prototype. The Gibson Les Paul appeared soon after to compete with the Broadcaster.
String-through body
When discussing electric guitar construction, the term string-through body is used to describe a type of solid body electric guitar body in which the strings are threaded through holes drilled into the bottom of the guitar body. The strings are typically held in place using metal ferrules screwed or glued into the holes.
The advantages of a string-through body mostly relate to improvements in a guitar's sustain and timbre. It is also by nature impossible to install a tremolo arm and have the string ends anchored through the body. Tremolo systems change string tension by changing the physical length of the string. This requires the end of the string to be anchored to the (tremolo) bridge unit directly, instead of to the wood of the body. [A talented guitar luthier or repair person is certainly capable of installing a tremolo bridge on this type of guitar, however, this is rarely done as it eliminates whatever tonal benefits are provided by the string-through body system and permanently degrades the value and collectability of the original instrument.]
Examples of string-through bodies on guitars include the Fender Telecaster Thinline and Telecaster Deluxe.
Semi-acoustic
An Epiphone brand semi-acoustic hollow-body guitar.
These guitars have a hollow body and electronic pickups mounted on its body. They work in a similar way to solid body electric guitars except that because the hollow body also vibrates, the pickups convert a combination of string and body vibration into an electrical signal. A variant form, the semi-hollow body guitar, strikes a balance between the characteristics of solid-body and hollow-body guitars. Advocates of semi-hollow-body guitars[who?] argue that they have greater resonance and sustain than true solid-body guitars, as a solid wood body. Several metal bodies were made in the 1950s by violin and cello makers. In the 1970s, John Veleno made a polished aluminum guitar. Liquid Metal Guitars makes a metal body guitar made out of a solid block of aluminum and then chrome or gold-plates the instrument. Many guitars otherwise sold as solid-bodied instruments, such as the Gibson Les Paul or the PRS Singlecut, are built with "weight relief" holes bored into the body which affect the sound of the instrument. The Les Paul Supreme edition is currently described by the manufacturer as a "chambered" instrument, with a weight relief system designed to positively affect the sound.
Electric acoustic
Some steel-string acoustic guitars are fitted with pickups purely as an alternative to using a separate microphone. They may also be fitted with a piezoelectric pickup under the bridge, attached to the bridge mounting plate, or with a low mass microphone (usually a condenser mic) inside the body of the guitar that will convert the vibrations in the body into electronic signals, or even combinations of these types of pickups, with an integral mixer/preamp/graphic equalizer. These are called electric acoustic guitars, and are regarded as acoustic guitars rather than electric guitars because the pickups do not produce a signal directly from the vibration of the strings, but rather from the vibration of the guitar top or body. These should not be confused with semi-acoustic guitars, which have pickups of the type found on solid body electric guitars.
String, bridge, and neck variants
Although rare, the one-string guitar is sometimes heard, particularly in Delta blues, where improvised folk instruments were popular in the 1930s and 1940s. Eddie "One String" Jones had some regional success with a Mississippi blues musician Lonnie Pitchford played a similar, homemade instrument. In a more contemporary style, Little Willie Joe, the inventor of the Unitar, had a rhythm and blues instrumental hit in the 1950s with "Twitchy", recorded with the Rene Hall Orchestra. The best-known exponent of the four-string guitar, often called the tenor guitar was Tiny Grimes, who played on 52nd Street with the beboppers and played a major role in the Prestige Blues Swingers. Grimes' guitar omitted the bottom two strings. Deron Miller of CKY only uses four strings, but plays a six string guitar with the two highest strings removed. Many banjo players use this tuning: DGBE, mostly in Dixieland. Guitar players find this an easier transition than learning plectrum or tenor tuning.
Seven-string
Most Seven-string guitars add a low "B" string below the low "E". Both electric and classical guitars exist designed for this tuning. A high "A" string above the high "E" instead of the low "B" is sometimes used. Another less common seven-string arrangement is a second G string situated beside the standard G string and tuned an octave higher, in the same manner as a twelve-stringed guitar (see below). Jazz guitarists using a seven-string include veteran jazz guitarists George Van Eps, Bucky Pizzarelli and his son John Pizzarelli.
Seven-string electric guitars were popularized among rock players in the 1980s by Steve Vai. Along with the Japanese guitar company Ibanez, Vai created the Universe series seven string guitars in the 1980s, with a double locking tremolo system for a seven string guitar. These models were based on Vai's six string signature series, the Ibanez Jem. Seven-string guitars experienced a resurgence in popularity in the 2000s, championed by Linkin Park, Slayer, KoRn, Fear Factory, Strapping Young Lad, Nevermore, and other hard rock/metal bands. Metal musicians often prefer the seven-string guitar for its extended lower range. The seven-string guitar has also played an essential role in progressive metal rock, and is commonly used in bands such as Dream Theater, Pain of Salvation and by experimental guitarists such as Ben Levin.
Eight and nine-string
Eight-string electric guitars are rare, but not unused. One is played by Charlie Hunter (manufactured by Novax Guitars). The largest manufacturer of 8- to 14-strings is Warr Guitars. Their models are used by Trey Gunn (ex King Crimson) who has his own signature line from the company. Also, Mårten Hagström and Fredrik Thordendal of Meshuggah used 8-string guitars made by Nevborn Guitars and now guitars by Ibanez. Munky of nu metal band KoRn is also known to use seven-string Ibanez guitars and it is rumored that he is planning to release a K8 eight-string guitar similar to his K7 seven-string guitar. Stephen Carpenter of Deftones also switched from 7 to 8 string in 2008 and released his signature STEF B-8 with ESP Guitars. In 2008 Ibanez released the Ibanez RG2228-GK which is the first mass produced eight-string guitar. Jethro Tull's first album uses a nine-string guitar on one track. Minarik Guitars manufactures the "Inferno V" 9 stringed guitar that has the top three strings doubled up with strings that are an octave higher, like 12 stringed guitars. Bill Kelliher, guitarist for the heavy metal group Mastodon, worked with First Act on a custom mass-produced nine-string guitar.
Ten-string
B.C.Rich manufacture a ten-string six-course electric guitar known as the Bich, whose radical shape was specifically designed to allow the machine heads for the four secondary strings to be positioned on the body, avoiding the head-heaviness of many electric twelve-string guitars. However many players bought it for the body shape or electrics and simply removed the extra strings. The company recognized this and released six-string models of the Bich, but ten-string models also remain in production.
In October 2008, a ten-string electric jazz guitar by Mike Shishkov was demonstrated at the 3rd International Ten String Guitar Festival. This instrument was based on the ten-string extended-range classical guitar.
Twelve-string
Twelve string electric guitars feature six pairs of strings, usually with each pair tuned to the same note. The extra E, A, D, and G strings add a note one octave above, and the extra B and E strings are in unison. The pairs of strings are played together as one, so the technique and tuning are the same as a conventional guitar, although creating a much fuller tone. They are used almost solely to play harmony and rhythm. They are relatively common in folk rock music. Lead Belly is the folk artist most identified with the twelve-string guitar, usually acoustic with a pickup.
George Harrison of The Beatles and Roger McGuinn of The Byrds brought the electric twelve-string to notability in rock and roll. During the Beatles' first trip to the US, in February 1964, Harrison received a new "360/12" model guitar from the Rickenbacker company, a 12-string electric made to look onstage like a 6-string. He began using the 360 in the studio on Lennon's "You Can't Do That" and other songs. Roger McGuinn began using electric 12-string guitars to create the jangly sound of The Byrds. Another notable guitarist to utilize electric 12-string guitars is Jimmy Page, the guitarist with hard rock-heavy metal and rock group Led Zeppelin.
3rd bridge
The 3rd bridge guitar is an electric prepared guitar with an additional 3rd bridge. This can be a normal guitar with for instance a screwdriver placed under the strings, but can also be a custom made instrument. Lee Ranaldo of Sonic Youth plays with a 3rd bridge.
Double neck guitar 
Double neck (or, less commonly, "twin-neck") guitars enable guitarists to play guitar and bass guitar or, more commonly, a six-string and twelve-string. An early user was John McLaughlin, but the double-neck guitar was popularized by Jimmy Page, who used a custom-made Gibson EDS-1275 to perform the "Stairway to Heaven" and "The Song Remains the Same", although "Stairway to Heaven" was actually recorded using a Fender Telecaster. Don Felder also used the Gibson EDS-1275 during the Hotel California tour.
