Nick Doshi created a headphone amplifier for his own use for location recording that turned out so well that he decided to make more. The Doshi headphone amp ($3795 MSRP) employs custom-made Sowter output transformers coupled with high-voltage drive circuitry to provide maximum power into three impedance load ranges. With a discrete differential volume control that uses the same relays as the Doshi preamplifier, and an amplifier section that has three separate regulators per channel in addition to direct coupling from input to output . . .