Eric Clapton’s 1966 Marshall JTM45/100

Eric was seen using a Marshall JTM45/100 (or Marshall Super 100 – depending on how you prefer to call it) during the Cream era. This amp was developed by Jim Marshall upon a request from Pete Townshend of The Who, who wanted a more powerful version of the 50W Marshall amp that he was using at the time (circa 1965).

I went to Jim Marshall, stomped down my 50-watt amp and said, ‘I want that twice as loud,’” Townshend says. “And, almost like Krupps, the famous military manufacturer, Jim Marshall’s eyes lit up. He said, ‘I will supply this man with the weapon he requires.’ And out of that came the Marshall stack and the big amplifiers of the Sixties.”

Guitar World, September 2002, an excerpt from ‘History of Marshall Amps’

The JTM45/100 model went through a few different incarnations between 1965 and 1966, and Eric himself most likely used the version with the KT66 output tubes (as opposed to EL34s which were used on later models), and Drake 1204-43 power transformer (as opposed to a Radiospares transformer on the previous version).

Interesting to note, another guitarist that was becoming popular at that time by the name of Jimi Hendrix, purchased a pair of JTM45/100s himself upon landing his feet in the UK in late 1966. This means that both Fresh Cream and Are You Experienced were likely recorded on the same exact model of an amp, which explains why so many people consider this to be the best amp that Marshall has ever put out.

[I use] Two 100-watt Marshalls. I set them full on everything, full treble, full base, and full presence, same with the controls on the guitar. If you’ve got the amp and guitar full, there is so much volume that you can get it 100 miles away and it’s going to feedback – the sustaining effect – and anywhere in the vicinity, it’s going to feedback.

Eric Clapton: The Rolling Stone Interview

Usage

It is unknown for how long Clapton used the KT66 version, but based on the photos, he did switch to the newer version with EL34s at some point after 1967 (when the new version was introduced). Most concrete proof of this is a photo taken at Blind Faith’s Hyde Park concert in London, on June 7, 1969.

The photo (displayed below) clearly shows that there’s a backplate on the Marshall reading “Super Lead 100”, and that the amp has a “Cream” stamp – meaning that it was used during that era. This is significant because although identical from the front, these are two very different amps, and the earlier version can be easily be identified by its backplate, which reads “Super 100 Amplifier” as opposed to what can be seen in the photo below. [The Evolution of the 100W Circuit: From JTMs to JMP Superleads]

The point is – the switch to the newer model did happen while Clapton was still playing with Cream, it’s just that we don’t know when exactly. This, of course, opens up the possibility that Fresh Cream was recorded on the earlier version of the JTM45, while Disraeli Gears was on the newer Super Lead.