The Marshall ‘Bluesbreaker’ model was one of the defining amps of the 1960s, though it was rapidly eclipsed by much higher powered and ever-louder models. The real, original name was the Marshall Model 1961, a 30 watt combo amp with 4×10 inch speakers built for Eric Clapton. That was quickly replaced with a 2×12 version, the Model 1962. A 1965 built Model 1962 was what Clapton used while in John Mayall’s Bluesbreakers, and that gave the amp its nickname. The Model 1962 was produced from 1964 to 1972.
What we’re looking at here is a reissue of the JTM45 Tremolo Bluesbreaker amp, this one built at Bletchley, England in 1990. It is labelled as a “Tremelo 50” (yes, that’s Marshall’s own mis-spelling of Tremolo) but it actually puts out a little less wattage.
Although the Marshall JTM45 can put out about 45 watts when driven into full distortion, it typically puts out about 30 to 35 watts of clean power and really should be considered a 30-watt amp. This flexibility in power rating is often the case with Marshall amps. Some will put out more than the stated power rating and some less.
Several different series of very early Marshall models were identified with the “JTM” prefix, such as JTM45, JTM50 and JTM45/100. JTM stands for Jim and Terry Marshall. Terry is Jim’s son, who worked for the Marshall company on and off for years, mainly involved in artist relations.
Output wattage – rated 50w (but see above)
Outputs – 2 x 1/4″ jack speaker outputs, selectable 16Ω/ 8Ω / 4Ω load
Channels – 2
Inputs – 4 x 1/4″ jack instrument inputs (2 x high, 2 x low)
Controls – Tremolo speed, tremolo intensity, bass, middle, treble, volume I, volume II
Speaker configuration – 2 x 12″
Speaker model – Celestion G12M-25 (16Ω, 25w)
Unit impedance – 8Ω
Preamp valves – 3 x ECC83, 1 x ECC83
Power amp valves – 2 x 5881
Rectifier – 1 x GZ34
Footswitch – included
This 2 x 12” reissue combo has the legendary deep blues tone created by the classic Marshall circuit with a GZ34 valve rectifier, similar to the original JTM45. However, with two re-issued Celestion Greenback speakers its sonic characteristics differentiate it and give it that recognisable sound. This Marshall classic may not shout the loudest but its vintage tone means its personality stands out from the crowd.
This amp is in fabulous condition and perfect working order. It has been in a home studio for the last 15 or so years, never out on the road, and always looked after very well by a fastidious owner.
It presents in excellent order, with no scuffs or tears to the tolex, and only a tiny blemish on the front grille cloth on the lower left side. It is in completely original condition, with no changes or modifications. It still has its original output valves in place. There has been no work done to this amp since it came out of the factory, because none has ever been needed.
The two Celestion G12M 25 watt Greenback speakers are a perfect match for this amp. The tubes are 5881’s, a change from the original design KT66. This change was due to the KT66 being out of production at the time of reissue. As noted, though the inside back panel on the chassis clearly says ‘Tremelo 50’, the amp actually puts out between 30 and 35 watts.
And yes, it has wheels !
A killer classic Marshall reissue in excellent condition, waiting for the chance to blow away some cobwebs at your favourite venue.