The name infinity graced amps a few years ago. Now the parent company (The Harmon Group) is also made up of Harmon/Kardon and JBL. H/K has been supplying OEM car audio equipment for a long time now (most notably in BMW's) and JBL makes both OEM and aftermarket systems for the 12V industry.

So, who knows who actually designed and manufactured that line of amps (the Beta's) but they were marketed under the brand name of Infinity.