Marshall Amplification: Wikis


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Marshall Amplification
Founded London, United Kingdom (1960)
Founder(s) Jim Marshall
Headquarters Bletchley, Milton Keynes, United Kingdom
Industry amplification, musical instrument manufacturing
A 3 x 6 stack of Marshall ModeFour guitar cabinets on the main stage of Tuska Open Air Metal Festival in 2008. This setup belongs to Jeff Hanneman of Slayer.

Marshall Amplification is a British company which designs and manufactures music amplifiers. Marshall amplifiers, and specifically their guitar amplifiers, are among one of the most recognized icons in popular music. Marshall is based in Bletchley, Milton Keynes. Marshall amps were originally built as direct copies of Fender amplifiers. However, they were soon modified, and would begin to incorporate certain traits which made them more favourable to guitarists seeking a heavier sound. The distinctive Marshall 'crunch' distortion sound has remained sought after for nearly half a century. Like many high end guitar amplifiers, many of the current (and reissue) models continue to use vacuum tubes as amplification components. Marshall also manufactures less expensive solid state and hybrid devices.

It is an important sponsor of sport in the locality: as of mid 2009, it sponsors Marshall Milton Keynes Athletic Club as well as Marshall Milton Keynes Lions basketball Club.[1]

The famous Marshall sound is distinctive and legendary; the sound of a Marshall 1959 SLP or JCM800 amp is among the most recognised in popular music, and there is a constant demand for both cutting edge and vintage amplifiers.





After a successful career as a drummer and teacher of drum technique, Jim Marshall first went into business in the early 1960s with a small shop in Hanwell, London, selling drums, cymbals and drum-related accessories; Marshall himself also gave drum lessons. According to Jim, Ritchie Blackmore, Pete Townshend and other guitarists often came into the shop and asked why Marshall was not selling or producing guitar equipment.[2] Marshall Ltd. later expanded and started selling guitars and amplifiers, the most notable of which at the time were the Fender amplifiers imported from America. These were very popular with guitarists and bass players, but were very expensive.

Design of first amplifier

Jim Marshall thought he could produce an equivalent product for less money, but he had limited experience as an electrical engineer. He enlisted the help of his shop repairman Ken Bran and an EMI technician named Dudley Craven, and between them they decided they most liked the sound of the 4x10" Fender Bassman. They made several prototypes using the Fender Bassman amp as a model. The sixth prototype was in Jim's words, the "Marshall Sound".[3]

The first few production units were engineered to be almost exactly the same as the Bassman circuit, with US-origin transformers and military surplus 5881 power valves. The major difference however was the cabinet used, as Marshall decided to build separate amplifiers and speaker cabinets, and as they were originally intended as bass amplifiers, Marshall chose to use four 12-inch Celestion speakers in a closed-back cabinet instead of the Bassman's four 10-inch Jensen speakers in an open-back cabinet. This new amplifier, tentatively called the "Mark II", was eventually named the "JTM45" after Jim and his son Terry Marshall, and "45" as, in theory, it produced 45W of power.en blablabla

Distribution deal

Jim Marshall entered into a 15-year distribution deal with British company Rose-Morris during 1965, which had given him the capital to expand his manufacturing operations, though it would prove to be costly. In retrospect, Marshall admitted the Rose-Morris deal was "the biggest mistake I ever made. Rose-Morris hadn't a clue, really. For export, they added 55% onto my price, which pretty much priced us out of the world market for a long time."[4]

'Park' amplification

The new contract had disenfranchised several of Marshall's key players in the early British distribution system he had set up. Among them was Jim's old friend Johnny Jones. To accommodate his friend, Marshall launched the Park brand name. These were essentially Marshall amps, but the nameplate said "Park" (the maiden name of Jones's wife, Margaret), which Jones could then distribute without violating the Rose-Morris contract.

The Park line would also be used over the years for experimental models and other products Rose-Morris wasn't interested in. Other brand names Marshall Amplification had used for various business reasons included Big M (for the former West German market), Kitchen/Marshall (for the Kitchen Music retail chain in North London), Narb (Ken Bran's surname spelled backwards) and CMI (Cleartone Musical Instruments). Amplifiers sold under these brand names are quite rare, and fetch high-dollar values on today's collectors market.[5]

Change to UK sourced parts

In search of lower production costs, Marshall quickly started sourcing parts from the UK. This led to the use of Dagnall- and Drake-made transformers, and a switch to the Marconi-Osram Valve Company’s KT66 valve instead of the 6L6 tube commonly used in the United States.

This gave Marshall amplifiers a more aggressive voice which quickly found favour with players, most notably a young Eric Clapton, who would sit in Jim's shop practising his playing. When Clapton was invited to join John Mayall's Bluesbreakers, he asked Jim Marshall to produce a combo amp with tremolo which would fit in the boot of his car, and one of the most famous Marshall amps was born, the so called "Bluesbreaker" amp.[2] This is the amplifier that gave Clapton that famous tone on the Bluesbreakers' Beano album.

Other early customers included Pete Townshend and John Entwistle of The Who, whose search for extra volume led Marshall to design the classic 100-watt valve amplifier. After the creation of the full "stack," the competition for volume between the two drove Pete to ask Jim to build him an amplifier with even more power[citation needed]. Jim Marshall was at this time employing Dudley Craven to build the amplifiers, who doubled the number of output valves used, along with using a larger power transformer and an extra output transformer. Around four of these amplifiers were built and delivered to Pete Townshend, and then the design was updated to form the now recognised SLP100 amplifier.

Another valve change

At this time, the KT66 valve was becoming more expensive, as the MOV Company faced greater competition from Mullard. Hence, another valve change was made, with Marshall starting to use European-made Mullard EL34 power stage valves.[6] These have a different overdrive character than the KT66's, which gave Marshalls a more aggressive voice still. In 1966, Marshall's most famous customer made his first appearance in England, and quickly found himself in Jim's shop. A young Jimi Hendrix was in Jim's shop with his manager, Chas Chandler, trying the amplifiers and guitars. Jim Marshall was suspicious of Hendrix at first, expecting him to be "another American wanting something for nothing" but to his surprise, Hendrix offered to buy the amplifiers outright at retail price, if Jim would provide him with support for them around the world.[2] Jim Marshall agreed, and several of Hendrix's road crew were trained in the repair and maintenance of the Marshall amps through the years.

The amplifiers from this era are easily identifiable by their acrylic glass (a.k.a. Plexiglas) front panel, which earned them the nickname, "Plexi"s. These now have significant collectors' value. Amplifiers from the 1970s onwards can be distinguished most easily by their brushed metal front panel, and are known as "ali panel" Marshalls. After 1973, in order to streamline production, the inefficient hand wiring was discontinued and Marshall valve amplifiers were switched to printed-circuit-board paths (PCBs). The result is that some vintage purists claimed the sound to be more "sterile", although the PCB itself does not change the sound. There was probably a slight change in components on the pcb which is a hotly debated topic within the musician community to this day. Also, much of the tonal debate between the plexi- and aluminium-panel Marshall amps comes from the fact that in 1974 Marshall's US distributor had them change all of the amps sold in the US and Japan over to the much more rugged 6550 instead of the EL34 output tube. This produced a much different sound than the EL34—a sound perceived as less smooth and more metallic when overdriven. This change was brought about due to reliability problems with the EL34's, and the 6550 generally allowed the amps to make it through warranty without problems. The circuit changes required to switch the amps were very minor, and it was easy to change from the 6550 to the EL34 or vice versa by changing a few resistor values, moving the tap for the feedback loop and rebiasing the amp. The mystique surrounding the Plexi series only increased due to the roar first heard on Van Halen's 1978 eponymous debut. Eddie van Halen modified his amps and cranked them up to get his now famous 'brown' sound.

Mid-1970s and 1980s

In the mid-1970s, Marshall introduced the "master volume" ("MV") series, which was initially called the "JMP." This was in response to the demand for yet more distortion, and many techs had been modifying the amps for years by connecting the two input stages in series rather than parallel as in the original Marshalls. A master volume was introduced to make the volume levels more manageable. This gave the new breed of Marshalls a different voice, more cutting and edgy, which later found favour with players such as Randy Rhoads, Zakk Wylde and Slash. Soon after the Rose-Morris deal had ended in late 1980, Marshall began calling this series the "JCM800" series (named after both Marshall himself and the license plate of his car, which he'd had since 1972)[7]. Marshall made several amplifiers under the "JCM800" name, but most noticeably were the 50 watt 2204 and the 100 watt 2203. Because the valve industry had begun to fade and Marshall became worried that the standard power valve, the venerable EL34 would soon become unavailable, a number of JCM 800s were factory equipped with the 6550 beam pentode power valve, a valve with a different tonal character. Some people (notably Ozzy Osbourne guitarist Zakk Wylde) loved the resulting sound, but it was generally considered to be a downgrade in sound quality. The 6550 is a high power tube that is more common in valve-driven bass amplifiers because it allows a higher output power over the EL34 for a given distortion level and because it has a very crisp low and high end sound. Because many players desired more power amp distortion (which is considered more "pleasant" than pre-amp distortion, which these Marshalls still had plenty of), the prices for EL34s, especially vintage ones, skyrocketed for use in Marshalls. Marshall would not return to full time use of the EL34 in all of its valve amps until the rise of vacuum tube factories in the mid and late 90s when former Soviet countries made most valve types plentiful again.

Competition from American amplifier companies

Marshall began to see more competition from American amplifier companies such as Mesa Boogie and Soldano. Marshall then updated the JCM800 range with additional models and new features such as "channel switching," which meant that players could switch between clean and distorted tones with the push of a foot-operated switch. This feature debuted in the 2205 series and these amps contained more pre-amp gain than ever thanks to a new innovation; diode clipping. This meant a solid-state diode added additional distortion to the signal path, akin to adding a distortion pedal. While hotly criticised today among valve purists, these amps were more popular than ever, finding mass acceptance within the hard rock community and still in use today by many. Marshall around this time began further experiments with solid-state amplifiers, which were increasingly improving in quality due to technological innovations but were still considered beginner level equipment. Regardless, solid-state product lines with the Marshall name on them were and still are a wild (if critically discounted) success for the company, allowing the entry level guitarist to play the same brand of amp as his or her heroes.

The 1990s

In the 1990s, Marshall updated its product line again with the JCM900 series. Reviewed by Guitarist magazine in the UK and given the line, "Shredders, here is an amp you won't need to have modified," this move by Marshall was again an outgrowth of musicians' desires, featuring more distortion than ever and retaining popular aspects of the late JCM800 models. However despite such marketing claims they were not as hi-gain as advertised and lacked a full gain stage. Marshall rectified this with the SL-X series (as used by Tom Johnson of Darkhorse or the group Kiss). This model was one channel and was given an additional pre-amp ECC83/12AX7 instead of diode-based distortion. Still, if not for shredders, the JCM900 was well received by younger players associated with pop, rock, punk and grunge which was widespread by the early 90's.

Although the EL34 had at this time begun to return to prominence, a number of these were shipped with 5881 valves, a now uncommon valve similar in tone and build to a 6L6. Around this time, Marshall released a few "special edition" amps in this range, including a "Slash Signature" model, a first for the company, and the Silver Jubilee.

Current Models

Marshall currently produces a number of amplifiers which are a mix of modern designs and vintage reissues. Most models attempt to include the "classic" Marshall "roar."

Modern Series

Marshall currently produces a wide range of amps with the distinctive looks and sound of the Marshall valve amp. The longest running "current" model is the JCM2000 range, which is split into the two channel and three channel series, known as the Dual and Triple Super Leads respectively. These amps are a continuation of the JCM800 and 900 series, although the controversial diode clipping circuit used in the later 800 and 900 amps has been removed in favour of additional valve gain stages. Although lumped together as JCM2000 models the DSL and the TSL have different circuits and are more distantly related than the model range suggests. The DSL is a solid extension of the JCM800 series with several sound enhancements and is perfect as an all-round workhorse for many genres of music. The TSL came with similar functions but was targeted at more modern grunge or nu-metal genres.

The newest flagship modern amplifier is the JVM, which comes in a wide variety of models and ranges and is designed as an ultra modern amp for the newer breed of guitar players. The JVM series can be seen as an evolution of the JCM 2000 series (although the 2000 series is still produced), as it has a wide variety of options and channels available, while still providing a modern flavour on the classic Marshall tone.

Around the same time as the release of the full featured JVM, Marshall also released a new amp called the Vintage Modern, which is designed to be a much simpler amp, boasting a single channel and designed to be controlled more by the player's style and guitar than by channel switching or multiple settings, reminiscent of the vintage "Plexi" and JCM800 range, but with modern conveniences such as foot-switchable distortion levels and reverb.

Vintage series

Marshall periodically will discontinue a model of amplifier, and reissue it later. Currently, a significant portion of Marshall's valve amp lineup are reissues. In 2001 Marshall reissued many of its amplifiers of yesteryears. The most popular and well known of these is the Model 1959-SLP, which is designed to be a reissue of the late 60s era "Plexi" amplifier, but which are in reality reissues of the post-1973 Super Lead models in that they use printed circuit boards internally for ease of production. The original design utilised hand wired circuits on turret boards, which is now available for a premium in the "hand wired" series. The actual difference in sound between the circuit paths is debatable, with some insisting PCB design is inferior and others (including Randall Smith of Mesa/Boogie) saying that the difference is negligible. Other reissues are similarly PCB designed, even where the originals were hand wired, except where explicitly noted (i.e. the "hand wired" range currently offered). Other models in the Vintage series include the 1987x (the 50W version of the 100w 1959SLP, used by some, including Yngwie Malmsteen for its lower headroom and "early" distortion curve), the 100 watt valve driven JCM800 2203 (used extensively by Zakk Wylde and both Jeff Hanneman and Kerry King of Slayer), the JCM900 4100, the JTM45 2245, and the 1962 combo, also known as the "Bluesbreaker" for its famous use by Eric Clapton with John Mayall's Bluesbreakers.

Marshall has also recently introduced a handful of hand-wired reissues, using old-fashioned manufacturing techniques whereby the circuit is hand mounted on "turret boards." These have small metal stakes to which the components and leads are soldered, as compared to PCB, wherein the components are print-mounted by computer to the board, leads placed through the board, and soldered in place. The amps are "true" reissues of the 100 Watt 1959 "Plexi" a 20-Watt 2061x, and a 1974x 18-Watt model, which is a combo amp. The cabinet marketed as the match to the head version, as well as the combo, use special Celestion re-issued 55 Hz version of the popular "greenback" speaker, which Celestion has made available under its "Heritage" series.

Solid-state amplifiers

While renowned for their valve guitar amps, Marshall produces and sells a large amount of solid state and bass equipment. Marshall's "Valvestate" amplifiers were at the time seen as evolutionary, as they contained a hybrid of valve and solid state technology, to provide a modicum of "true" valve tone, along with transistor reliability and ease of maintenance. Currently named the "AVT series" (although these are now out of production, being replaced with the "AVT tribute" for a short time), there are a number of different models, all of which are cheaper than their all-valve counterparts. It is Marshall's current line of "hybrid" amplifier, featuring a 12AX7 preamp tube employed in the preamp (to "warm up" the signal) as well as solid state components, with a solid-state power amp. These are considered and marketed as intermediate-level equipment to bridge the gap between the higher valve range and lower range MG series. Some feel they offer a quality and sound close to Marshall's higher end equipment. These amps are fairly popular in the metal music community for their quick response time. A minor controversy arose from this amp series as some unscrupulous dealers attempted to market them as "valve amps" to unsuspecting customers.

In January 2009 Marshall released their latest variant of the MG line of practice amplifiers. Replacing the popular MG3 line, the MG4 has been designed to offer the guitarist a whole host of features whilst keeping the control of the amplifier simple. The tone of the amplifier is considered to be slightly better than the previous versions and is generated through analogue circuitry which is considered far superior quality to digital options that are available from other manufacturers at this price level. Other features such as custom voiced effects and Marshall's revolutionary new Stompware footswitching technology add further flexibility to the line. Immense supply and marketing of this amplifier leads to the overwhelming sales attributed to the MG Series.

Marshall also sell a small series of miniature amplifiers, called the "MS" series. This range consists of only two amps, the MS-2 and the MS-4 (the MS-2 though has several varying colour schemes, based on classic Marshall amps). Neither exceed 25 cm in height, so are very portable. They are priced quite low as well. Both can be powered by 9 volt battery or through a DC mains adapter.

Bass series

Although Marshall Amplification is well known for its guitar amplifiers and speaker cabinets, it also produces bass amplifiers. Marshall currently manufactures a professional, all-valve bass rig called the VBA400. It houses no less than eight 6550 power valves plus three ECC83 and one ECC82 preamp valves. The controls have been kept to a minimum and consist of a 3-band passive EQ network for Bass, Middle and Treble, which can be totally reconfigured by the means of a 3-position contour switch. Further tone control is provided by Deep and Bright switches. The input accommodates both Active and Passive bass pickups; there is also an XLR DI output for recording complete with Earth (grounding) lift and Pre/Post EQ switches. There is also a series FX loop, a tuner mute and a speed control for the fan that cools the power valves.

Two extension cabinets are available for the VBA, a 4x12” and an 8x10”. These cabinets have separate sealed chambers inside to prevent unwanted cabinet resonance and also add structural integrity. Both cabinets are loaded with custom design loudspeakers and give a total impedance of 4 ohms, the amplifier will drive loads of 2 ohms.

Other bass equipment currently available is the new MB range of amplifiers. The range consists of the MB15 (15 watt combo), MB30 (30 watt combo), MB60 (60 watt combo), MB150C (150 watt combo), MB4210C (450 watt 2x10” combo), MB4410 (450 watt 4x10” combo), MB450H (450 watt head) and three extension cabinets the MBC115 (1x15”), MBC410 (4x10”) and the MBC810 (8x10”). These units are mostly solid state, but have a single ECC83 preamp valve incorporated into the preamp, except in the MB15 and MB30 models.

Recently, Marshall has honoured Lemmy Kilmister with their first ever signature bass amp head. Based on his 100 watt super bass unit "Murder One", a rewired, oversized Marshall Super Lead head, they created a bass amp with an "...incredible sonic depth and an unbelievable tonal range".[3]

Model number confusion

Much confusion has arisen over the years due to Marshall's arbitrary method of naming each amp model, especially during its first few decades, when under Rose-Morris. For example, the models given the 1987 designation (in the late 1960s to 1970s), or the 1987x designation (in the 1990s and beyond) had nothing to do with the year 1987 nor was there any apparent relationship in the numbering to its direct counterpart the 1959 model, which was not made in 1959 either. This led to a "clean up" of the model numbering beginning with the JCM 2000 series, although reissues retain the original model numbers.

The Marshall Legacy

The classic Marshall Stack is one of the defining images behind loud rock music. A full stack consists of one head containing the actual amplifier, on top of two stacked 4x12s, which are loudspeaker cabinets each containing four 12 inch loudspeakers arranged in a square layout. The top cabinet has the top two loudspeakers angled slightly upwards, giving the Marshall stack a distinctive appearance. When a single cabinet is used, the complete unit is called a half stack.

In the early-mid 1960s, Pete Townshend and John Entwistle of The Who were directly responsible for the creation and widespread use of stacked Marshall cabinets. Pete later remarked that John started using Marshall Stacks in order to hear himself over Keith Moon's drums and Townshend himself also had to use them just to be heard over John. In fact, the very first 100 watt Marshall Amps were created specifically for Entwistle and Townshend when they were looking to replace some equipment that had been stolen from them. They approached Jim Marshall asking if it would be possible for him to make their new rigs more powerful than those they had lost, to which they were told that the cabinets would have to double in size. They agreed and six rigs of this prototype were manufactured, of which two each were given to Townshend and Entwistle and one each to Ronnie Lane and Steve Marriott of The Small Faces. These new "double" cabinets (each containing 8 speakers) proved too heavy and awkward to be transported practically, so The Who returned to Marshall asking if they could be cut in half and stacked, and although the double cabinets were left intact, the existing single cabinet models (each containing 4 speakers) were modified for stacking, which has become the norm for years to follow.[8]

Entwistle and Townshend both continued expanding and experimenting with their rigs, until (at a time when most bands still used 50 to 100W amps with single cabinets) they were both using twin Stacks, with each Stack powered by new experimental prototype 200W amps, each connected to the guitar via a Y-splitter. This, in turn, also had a strong influence on the band's contemporaries at the time, with Cream, The Jimi Hendrix Experience and Led Zeppelin following suit. However, due to the cost of transport, The Who could not afford to take their full rigs with them for their earliest overseas tours, thus Cream and Hendrix were the first to be seen to use this setup on a wide scale, particularly in America. Ironically, although The Who pioneered and directly contributed to the development of the "classic" Marshall sound and setup with their equipment being built/tweaked to their personal specifications, they would only use Marshalls for a couple of years before moving on to using Sound City equipment. Cream, and particularly Hendrix, would be widely (and incorrectly) credited with the invention of Marshall Stacks.

The search for volume was taken on its next logical step with the advent of "daisy chaining" two or more amplifiers together. As most amplifier channels have two inputs, the guitar signal being present on both sockets, the cunning musician hooked the spare input of one channel to an input on another amp. By 1969 Hendrix was daisy chaining four Stacks, incorporating both Marshall and Sound City amplifiers, as recommended to him by Townshend.[9]

This competition for greater volume and greater extremes was taken even further in the early 1970s by the band Blue Öyster Cult, which used an entire wall of full-stack Marshall Amplifiers as their backdrop. Artists such as Slayer and Yngwie Malmsteen also use walls of Marshalls. Both Kerry King and Jeff Hanneman of Slayer can be seen playing in front of a total of 24 cabinets, and Yngwie has used as many as 31. However, it is usually the case that far less are actually powered, as using this many could cause serious problems with the overall sound mix of a live show. In most cases these are "dummy cabs," which are onstage for visual impact, not actually played through. For ease of transportation and lifting, most of these actually do not even contain any speakers. The same goes for some of the amp heads in a scenario like this, as they are just the wooden frame with, in fact, no heavy inner workings.

Such is the ubiquity of the sight of a wall of Marshalls at a rock concert; many artists who do not even use them have the dummy stacks on stage. Rick Parfitt of Status Quo, for example has a wall of Marshalls, but actually uses a combination of Vox AC30 in Marshall cabinets and JCM900's.[10]

Marshall also produces "combo" amplifiers, which combine speaker and amp in one case; and several variations of the classic stack design including a Marshall micro stack and a mini stack, the latter of which is a transistor practice amp about 10 inches high which runs on batteries.

The Marshall micro stack was a smaller sized release of a Marshall amp. The original Marshall micro stack was produced from 1985-1991 and featured 12 watts of power.

See also


  1. ^ Marshall backing Lions all the way - Milton Keynes Today
  2. ^ a b c Jim Marshall Interview
  3. ^ [1]
  4. ^ History of Marshall from Guitar World Magazine, September 2002, page 84
  5. ^ History of Marshall from Guitar World Magazine, September 2002, page 86
  6. ^ Marshall Amps Info & Schematics
  7. ^ History of Marshall from Guitar World Magazine, September 2002, page 98
  8. ^ The Who's Marshall History
  9. ^ An interview with Pete Townshend from Guitarist magazine, August 1994
  10. ^ [2]

External links


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