{{Tone|date=July 2022}} {{Short description|Guitar amplifier}} {{EngvarB|date=July 2018}} thumb|Marshall JTM45 MK II Reissue The '''Marshall JTM45''' amplifier is the first guitar amplifier produced by the British company Marshall. It was initially produced in 1963, and has been ranked among the most desirable of the company's amplifiers.<ref name="pittman">{{cite book|last=Pittman|first=Aspen|title=The Tube Amp Book|year=2003|publisher=Hal Leonard|isbn=978-0-87930-767-7|pages=66, 68–69 |url=https://books.google.com/books?id=JT1I7Ld76YsC&pg=PA68}}</ref>
Notable musicians who have used this amplifier include David Gilmour,<ref name="Drozdowski" /> the Rolling Stones,<ref name="Drozdowski" /> and Jimi Hendrix,<ref name="Motter" /> among others.
==History and development == Prototyping of the JTM45 began in 1962, after London musical instrument retailer Jim Marshall decided to create a new amplifier in response to local guitarists' desire for an alternative to imported American Fender amplifiers. Marshall sought the advice of his shop repairman Ken Bran, who recommended electronics "whiz kid" Dudley Craven as the chief circuit designer. Marshall then arranged for Pete Townshend and Ritchie Blackmore demo prototypes to be constructed by Bran and Craven, settling on the sixth prototype as the production model.<ref name="Premier">{{cite web |last1=Brown |first1=Michael |title=Lust for Power |url=https://www.premierguitar.com/gear/lust-for-power |website=premierguitar.com |date=28 November 2013 |publisher=Premier Guitar |access-date=6 December 2021}}</ref>
This model was dubbed the "JTM45" – for Jim and his son Terry Marshall, and 45 for the RMS-rated wattage<ref name="Motter">{{cite web |last1=Motter |first1=Paul |last2=Schu |first2=Peter |title=A History Of Marshall Amps: The Early Years |url=https://reverb.com/news/a-history-of-marshall-amps-the-early-years |website=reverb.com |date=7 May 2015 |publisher=Reverb |access-date=7 December 2021}}</ref> – the amplifier mimicked the circuitry of the Fender Bassman but had an all-aluminum chassis, and a 12AX7 valve as the first in the chain (while the Bassman had a 12AY7). In addition, it featured Celestion speakers with a closed cabinet (rather than open-backed Jensen speakers), and a modified negative feedback circuit, which affected the harmonics produced by the amplifier.{{Citation needed|date=March 2024}}
As Bran later said, "The JTM also had different harmonic content, and this was due to the large amount of feedback that Dudley Craven had given it."<ref name="doyle">{{cite book|last=Doyle|first=Michael|title=The History of Marshall: The Illustrated Story of "The Sound of Rock"|year=1993|publisher=Hal Leonard|isbn=978-0-7935-2509-6|pages=17–22|chapter-url=https://books.google.com/books?id=E90tMBs9_FEC&pg=PA21|chapter=The JTM Series 1962–1966}}</ref> Early versions used 6L6 or US 5881 valves (a version of the 6L6<ref>{{cite book|last=Hunter|first=Dave|title=Guitar Rigs: Classic Guitar & Amp Combinations|year=2005 |publisher=Hal Leonard|isbn=978-0-87930-851-3|url=https://books.google.com/books?id=p1-kULtG9tgC&pg=PA111|page=111}}</ref>) in the output stage; later models used KT66 (from 1964), EL34 (from 1966), or KT88 (from 1967; in the 200W Major), and ECC83 (12AX7) valves in the pre-amplification stage.<ref name="pittman" /> The amplifier was also available in the bass format (although this model lacked a "bright" capacitor) and an additional PA version (which lacked a "mixer" capacitor).<ref name="doyle" /> Because of its power, Marshall decided early on to build it as a "head," with a separate 4×12" cabinet with Celestion speakers.
The first-ever use of this JTM 45 model in a live performance was in September 1963, when the amplifier was tested at the Ealing Club, a short distance from the original Marshall shops.{{cn|date=December 2021}} By the mid-1960s, the JTM45 had become so popular that it began to supplant the ubiquitous Vox amplifiers, including the Vox AC50, even though the Vox amplifier was equally powerful to the Marshall amplifier.<ref>{{cite book|last=Hunter|first=Dave|title=Guitar Rigs: Classic Guitar & Amp Combinations|year=2005|publisher=Hal Leonard|isbn=978-0-87930-851-3|page=102}}</ref>
In late 1965, Marshall introduced its now standard script lettering, in white. By early 1966 it began calling the amplifiers "JTM 50".<ref name="doyle" /> Some 100 early models had red lettering, and are especially sought after by collectors.<ref name="pittman" /> Other cosmetic changes included a gradual change to different knobs. The JTM 45 became the basis for many subsequent Marshall amplifiers, most notably the Marshall 1962 combo (later referred to as the "Bluesbreaker" due to its use by Eric Clapton with John Mayall's Bluesbreakers).<ref>{{cite book|last=Batey|first=Rick|title=American Blues Guitar: An Illustrated History|year=2003|publisher=Hal Leonard|isbn=978-0-634-02759-8|url=https://books.google.com/books?id=10PtO6eF12UC&pg=PA106|page=106}}</ref> Production of this model ceased in 1966, but it was reissued in 1989, albeit with a modern printed circuit board and 6L6 output valves.<ref name="doyle" /> In 2014 Marshall reissued a "handwired" 30 W amplifier based on the JTM45, the 2245THW, whose circuitry is identical to the 1962 combo circuit; it is a "fine high-end piece" according to ''Vintage Guitar'', listed at $4,800.<ref name="childs">{{cite news|title=Bluesbreaker Redux: Marshall Handwired Series 2245THW head and 1960AHW Cabinet|last=Childs|first=Zac|date=October 2014|work=Vintage Guitar|page=130}}</ref>
==Name, numbering== The first JTM45s did not have the standard Marshall numbers that later amplifiers had; models that derived from the JTM 45 did not receive serial numbers until 1964–1965 when backplates began to be applied.<ref name=doyle /> However, at random some of the early amplifiers had serial numbers stamped into the chassis on their reverse side.
{|class="wikitable" |- ! Model number !! Watts !! Dates !! Features !! Notes |- |JTM45 || 35–45<ref>{{cite book|last1=Micheal|first1=Doyle|last2=Nick|first2=Bowcott|title=The History of Marshall – The First Fifty Years|pages=44, 48}}</ref> || 1963–1964 || 2 channels, 4 inputs || Also available in bass and PA versions |- | 1963 || 50 || 1965–1966 || 4 channels, 8 inputs || PA version; "JTM50 MK III" |- | 1985 || 45 || 1965–1966 || 2 channels, 4 inputs || PA version of JTM50 MK II |- | 1986 || 45 || 1965–1966 || High treble and normal channels || Bass version of JTM50 MK II |- | 1987 || 45 || 1965–1966 || High treble and normal channels || Lead version of JTM50 MK II; also with tremolo as Model T1987 |- | 1989 || 45 || 1965–1966 || For electronic organs || Also with tremolo as Model T1989 |- | JTM 45 (2245<ref>{{cite web|url=http://www.marshallamps.com/product.asp?productCode=2245%28JTM45%29|archive-url=https://web.archive.org/web/20060502062208/http://www.marshallamps.com/product.asp?productCode=2245(JTM45)|url-status=usurped|archive-date=May 2, 2006|title=Marshall Amps:: 2245 (JTM45)|publisher=Marshall Amplification|access-date=1 May 2013}}</ref>) || 30 || 1989– || 2 channels, 4 inputs || Reissue of original JTM45 (1987) |- | 2245THW<ref name=childs /> || 30 || 2014– || Handwired head, circuitry identical with Bluesbreaker |}
==Sound== For all of its differences when compared with the Bassman, the sound of the JTM45 is still described as "like a tweed Fender", and is favored for blues and rock rather than for hard rock and metal.<ref name=hunter>{{cite book|last=Hunter|first=Dave|title=The Guitar Amp Handbook: Understanding Tube Amplifiers and Getting Great Sounds|year=2005|publisher=Hal Leonard|isbn=978-0-87930-863-6|url=https://books.google.com/books?id=N9hAviH6gqEC&pg=PA75|pages=75–76}}</ref> The JTM 45 delivers a smooth Marshall sound with a warm bass response due to the EL34/KT66 valves.{{cn|date=April 2019}}
==Notable users== *Eric Clapton *Arthur Brown<ref name="Drozdowski">{{cite web |last1=Drozdowski |first1=Ted |title=Peter Green's 1964 Marshall JTM45 |url=https://www.premierguitar.com/peter-greens-1964-marshall-jtm45 |website=premierguitar.com |date=29 January 2020 |publisher=Premier Guitar |access-date=6 December 2021}}</ref> *John Entwistle<ref name="Motter"/> *David Gilmour<ref name="Drozdowski"/> *Eddy Grant<ref name="Drozdowski"/> *Peter Green<ref name="Drozdowski"/> *Jeff Beck *Jimi Hendrix<ref name="Motter"/> *Gary Moore (reissue)<ref>{{cite book|last=Prown|first=Pete|title=Gear Secrets of the Guitar Legends: How to Sound Like Your Favorite Players|year=2003 |publisher=Hal Leonard|isbn=978-0-87930-751-6|url=https://books.google.com/books?id=vqQjuzPrqIwC&pg=PA10|author2=Lisa Sharken|page=10}}</ref> *Pete Townshend<ref name="Motter"/> *Angus Young (live, Young has a JTM45 in an isolation box under the stage)<ref>{{cite book|last=Prown|first=Pete|title=Gear Secrets of the Guitar Legends: How to Sound Like Your Favorite Players|year=2003|publisher=Hal Leonard|isbn=978-0-87930-751-6|url=https://books.google.com/books?id=vqQjuzPrqIwC&pg=PA2|author2=Lisa Sharken |page=2}}</ref><ref>{{cite book|last=Newquist|first=H. P.|title=The hard rock masters|year=2004|publisher=Hal Leonard|isbn=978-0-87930-813-1|pages=23–24 |url=https://books.google.com/books?id=nOKYUcPvysMC&pg=PA23|author2=Rich Maloof}}</ref> *The Rolling Stones<ref name="Drozdowski"/>
==References== {{reflist|2}}
==External links== *{{Official website|https://www.marshall.com/}} *[http://www.marshallcombo.ru/news/marshall_1987x_plexi_pereizdanie_usilitelja_likhikh_70_80_kh_godov/2014-02-19-45 Marshall 1987X Plexi Review] (Russian) {{Marshall amplifiers}}
{{DEFAULTSORT:Marshall JTM 45}} Category:Instrument amplifiers Category:Marshall amplifiers Category:Valve amplifiers