The Dead were best experienced live, which is why the band gave careful consideration to the sound systems they built for their endless tours.
The Band first began to work with McIntosh, the high-end audio people, at Woodstock in 1969. They were so impressed with what McIntosh had created for that event that they soon started working with the company on what would become known as their "Wall of Sound."
The WoS debuted in 1974. Featuring 50 Mac amps (48 MC2300s amd twp MC350 mono amps, the total output of that first system was just shy of 30,000 watts--tiny by today's standards but massive back then. And not only was this system loud, it was distortion-free--something that few PA set-ups of the time could manage.
This association with McIntosh continued for many years. it's why the company is the official sponsor of the current Dead exhibition at the Rock and Roll Hall of Fame. It's called--naturally--The Long Strange Trip. Mac gear is being used as part of the exhibit.