Eric Clapton’s Marshall JTM45/100 Super Lead 100
Eric started using this amp sometime with the Cream, likely in mid to late 1967. The amp was an updated version of the 1966 Marshall JTM45/100 that Eric played at the beginning of the Cream, and most likely used to record ‘Fresh Cream’. To learn about the difference between the two older and the newer version please refer to The Evolution of the 100W Circuit: From JTMs to JMP Superleads. Most notably, the older version (Version 3B) used KT66s output tubes, while the newer version (version 5A) used EL34s.
It is also worth pointing out that Eric possibly also used other versions besides these two, but it’s very hard to differentiate the different version because from the front they all looked the same. You can only tell difference by looking inside the amp, or by looking at the back-plate. By the stroke of luck, there is actually a photo showing the back of one of Eric’s Marshalls, from which we can see that this Marshall reads “Super Lead 100”, meaning that it’s a newer version.
The photo above was taken at Blind Faith’s Hyde Park concert in London, on June 7, 1969, but since the amp reads “Cream” on the back, it was obviously also used with the Cream. To which extent, unfortunately, no one seems to know, but it is possible that Cream’s second and third albums were recorded on this newer version of the JTM45/100.