BALANCED CROSSFETTM HEADPHONE AMPLIFIER ZERO FEEDBACK | SINGLE VOLTAGE GAIN STAGE Mjolnir is the only dedicated headphone amp using an Circlotron-style topology with high-voltage JFET inputs and MOSFET outputs. Unlike other balanced headphone amps, Mjolnir is not simply two of the same amps in a box, with one run inverted. It’s a unique, inherently balanced stage that delivers both low complexity and very high performance.