1969 was a year giants rocked the earth, and they wanted big amps. By that point in history, rock music was the baddest man in the whole damn town. Stadiums and outdoor festivals was where the action was—Madison Square Garden for chrissakes. Fifty watts just wasn't enough to move that chick in the 61st row in her hand-embroidered bellbottoms. It wasn't as if nobody was filling the void—witness the stacks of Marshalls, mountains of Hiwatts, and truckloads of Dual Showmans doing more to promote tinnitus in a single generation since WWII.
Only In America
Ampeg needed to compete. The team of amp designer Bill Hughes and Roger Cox—with input from Bob Rufkahr and Dan Armstrong—set about to create what Cox referred to as "the biggest, nastiest bass amplifier the world had ever seen." Using the same sort of madness that drove Dr. Frankenstein, the team came up with a 300-watt all-tube phantasmagoria they called the Super Vacuum Tube—or SVT, to save on vowels. To fully grasp the monstrosity of their creation, the SVT's 300-watt output stomped the deafening 200-watt Marshall Major by a full 100-watts!
Unveiled at the 1969 NAMM show in Chicago, the SVT head alone weighed 95 lbs and contained fourteen tubes, six of which were massive 6146 power tubes. To heat all those tubes, massive transformers with magnetic fields powerful enough to cause genetic mutations were necessary. And what kind of speakers were able to handle all that power? Nothing less than two cabinets sporting eight ten-inch speakers and weighing 105 lbs. each.
After surveying his creation, Cox was actually concerned about potential liability—when your engineers warn of the possible harm their designs could cause, you'd better listen. Ampeg's management did and devised a warning label which read:
"THIS AMP IS CAPABLE OF DELIVERING SOUND PRESSURE LEVELS THAT MAY CAUSE PERMANENT HEARING DAMAGE."