The History of: JTM45

POSTED 5.07.17 IN NEWS

The History of: JTM45

Back to where it all began - the JTM45.

The first Marshall amp was constructed by Jim Marshall’s colleague Ken Bran, and his assistant Dudley Craven in 1962. Put together in the first ever Marshall location in Hanwell, London, Jim had some success selling Fender Bassman amps at the shop and decided to use this design as an inspiration for the first prototype. The variety of differences between the Bassman and Marshall created the unique tone that has been popular worldwide and synonymous with classic guitar tones for over 50 years.

The first prototype was built on a 2-inch deep aluminium chassis, and at the heart of the amplifier was a pair of 5881 output valves alongside three ECC83 preamp valves. Each of the two channels had high and low sensitivity inputs, a feature that has remained constant over 50 years to most Marshall amps. The original output was 35 Watts into a fixed speaker load of 16 Ohms. The foundation of this amp has remained unchanged fifty years on, and even at the early production stage it was noticeably more aggressive.

The JTM (Named after Jim and Terry Marshall, Jim’s son) went through a great deal of production changes. A notable one happening in 1964 when the change to KT66 output valves was made. This gave the amp a power increase to 40-45 Watts, and gave the amp more aggression and distortion, setting the scene for things to come.

 

After playing an important role in rock and guitar-based music, and being used by Pete Townshend, Eric Clapton and hundreds of other guitarists, the JTM went through a variety of models. Due to its volume and versatility, Lead, PA, Bass and Organ versions were made from 1962 until its original reissue date in 1989. The features of these amps differed from high treble and normal channels, 4 channels with 8 inputs for PA models and tremolo options built into the Organ models in 1989.

The JTM45 became the foundation for many Marshall amps, including the popular 1962 ‘Bluesbreaker’, and the amp is still available today as part of both the Vintage Re-Issue Series and the Handwired Series.

For a more detailed look in to the history of the JTM45, purchase a copy of The History of Marshall: The First Fifty Years.

Find out more about the 2245 JTM45 at https://marshallamps.com/products/amplifiers/vintage-re-issues/jtm45-2245/

Find out more about the Handwired 2245THW at https://marshallamps.com/products/amplifiers/handwired-series/2245thw/

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