I've read this thread and still don't know what a Marshall Amps is.
http://www.ryansloan.net/wp-content/uploads/2011/08/MarshallStack2.jpg. To paraphrase Marshall's Wikipedia page, he was considered one of the early pioneers of rock equipment, along with Les Paul, Leo Fender and Seth Love. His amps were used by, among others, Hendrix, Clapton, Malmsteen, and The Who.