I don't know if Jim Marshall's contribution to rock music is familiar enough to those outside of the guitar community. Seriously, he and Leo Fender (and not to take anything away from Vox, but I never thought Vox was as driven by one man's vision as Marshall and Fender, therefore I didn't include them though they rightfully belong there) are responsible for what I'd call an overwhelming majority of the signature sounds of rock and roll. Keyboard players and drummers will disagree, and vocalists too perhaps, but what made rock and roll more unique than the sound of an amplified guitar or bass, especially one turned up and distorted through a Marshall or Fender?
What is striking to me too is the longevity of the technology, where Marshall and Fender are almost an anachronism: They belong to a different time, a different era, yet their "old" technology is still highly sought after and used in everyday business by professionals in the music business. If you are a pro and you want a certain sound, you might look for a 1965 Fender Twin or a late 60's "Plexi" Marshall for it...electronics which are pushing the half-century age mark.
Can you imagine doing this in any other field or business where technology is a crucial part of the job?
This is a society that kisses the collective ass of something like the Apple/Mac corporation, where users are kept informed of the latest and greatest new device and told when it will be released so they can line up at a Mac/Apple store the night before to be first in line to buy it. Then after buying that one, sometimes less than a year later Mac comes back at them and says this newest version of *the same device* is the one to have, and the users boldly trek to the Mac store carrying a portable tent, folding lawn chair, warm blanket, and a jug of coffee to wait in line for the opening bell to be struck and the doors to swing open...
...all to buy an "updated" version of the device you bought 9 months ago.

Jim Marshall...his amps...the same things that worked in 1968, the same sounds people wanted then and loved then, you can still get them by plugging into a Marshall amp. None of the "version 2.2" crap, none of the waiting in line for an upgrade or two...you do the same thing Hendrix and all those cats did in the 60's and plug into the amp.
Or for convenience, buy an iRig interface for your iPhone, dial up the Marshall simulator (which is pretty cool), and rock out digitally for however long it takes before your iPhone is deemed obsolete and the line starts forming at the Mac store...

RIP Jim Marshall.
