In the history of Marshall Amps Hendrix has, retrospectively, obtained legendary status. 
The true history places primacy on The Who and the secondary on Eric Clapton & Cream. 

This is The Who's Marshall History

THE WHO

&


Where do we start cleaning up?

MARSHALL

Drums were for marching, leading into battle, they were loud.  The modern drum kit could be very loud when hit hard.  Moony hit 'em hard as did Baker.  The guitarists wanted to match them and over-power the screaming audience.  Entwhistle led Townshend on the journey to severe hearing problems.

64-65 John uses a JTM45 head with a 4x12 angled cab, Pete a 1964 blonde Fender Bassman (50W from which Marshall developed the JTM45)  on a flat Marshall 4x12.  These are not stacks - they put the cabs on stands to get better sound projection especially from low, or non-existent stages such as here at Cook's Ferry Inn (25th March 1965).  John got his JTM45 tweaked (KT66 replaced by EL34) to give more power and moved to two cabs to reduce blown speakers.  Pete joined him with the 2nd "dummy" cab underneath as the single was adequate for the Bassman (overloading the speakers was part of the sound).


The Fender/Marshall Stack, Johns side-by-side + 1963 Super P.A. 50W on floor - May-June 1965

In mid '65 Pete and John changed to two Vox AC100 (Super Beatle) each, presumably for their extra power.  Unfortunately the rating of 100W was nominal and the sound, when played on full, was poor. Reliability was similar with regular burn outs.


6th August

The story goes that John and Pete approached Marshall to make a 100W amp.  The reason was not spontaneous as the story implies - on 3rd September their van loaded with gear was stolen.  They rented some more Vox and toured Europe using the other bands gear.  In the mean time Marshall had rushed out some prototype 100W heads by of doubling the number of output valves and the expediency of using two JTM45 output transformers.  Furthermore they just enlarged the cabinet of the JTM45 and thus the Who's amps are described as JTM45-100.  They were the first 100 Watt Marshall Heads!


19th November

The next job was to manufacture the massive 8x12 cabinets of which only 6 were made - 2 each to Pete and John and two to the Small Faces (Ronnie Lane & Steve Marriott). They were an interesting design being open-backed at the top which would have reduced bass response.  They were massive and supposedly Pete asked if they could be cut in half, which couldn't be done.  Despite Marshall modifying the existing flat and angled cabs for stacking, the 8x12 were used for another year or so.


Note: open slot in back top half, top and bottom speakers in both cabs plugged in, the huge handles

    Pt 2

Source of many of these photos:

Graeme Pattingale, 2003