Balanced Audio Technology's Geoff Poor pats the fevered brow of the REX reference preamplifier ($18,500). With 18 tubes, no wonder it has a fever!

The two piece unit has an unconventional power supply—each box contains the complete power supply for one polarity, positive in the control module and negative in the power module. Further the power module is completely tube regulated and is filtered with custom BAT oil capacitors.

Each input can be customized. Speaking of customizing, BAT lets you change the current source tube in the gain stage with one of three options: 6C19 (stock), 6H30, or 5881. To make the change, you just remove the current source board (for the 6H30) or pop in the 5881 straight. Why would you want to? "Well, tube rolling is fun," Poor allowed, "but using the tube in the current source does mean that the type of tube can have a dramatic effect on the sound."

Heavy, man—and so is REX. The power module weighs in at 39lbs and the control module tips 40lbs.