Yep, a nod to Jim Marshall along with Pete Townshend for the equipment. Townshend pushed for 100 watt amps. Townshend also had Marshall build 8x12 speaker cabs, but roadies balked at trying to move them, thus the Marshall stack of two 4x12 cabs was born. Of course Townshend would later move on to Hiwatt gear, but he used Marshall equipment in the beginning.
Townshend allegedly moved on to Hiwatt after a billing dispute between Marshall and The Who's management.
That's one story, anyways.
Interesting thing about Townshend's Hiwatts is that he had his amp technician take all of the tone controls out of the circuit, so there was pretty much nothing working except the volume knob, nothing to degrade the signal between the guitar and the amp's power section.
I have a Gibson Les Paul with a similar feature. If you pull up on one of the tone knobs, it takes all four of the knobs out of the signal chain, adding a noticeable bit of boost to the output. Great for solos.