Pass Labs HPA-1 Headphone Amplifier

The new design uses double-shielded low noise toroidal transformers in external supply The new design uses double-shielded low noise toroidal transformers in an external supply connected via aviation-grade circular connectors using silver over oxygen-free copper. The power supply is dual mono with two transformers with lower radiated and mechanical noise. Noise is the most prominent part of THD+N at low levels, so by lowering noise we get better resolution and dynamics. The gain circuitry continues to use our favorite transistors from Toshiba but has a larger, higher biased, output stage like the Xs Preamp, and includes auto bias. The larger output stage makes longer, and multiple cable runs easier to drive and gives us the advantage of simplifying our single-ended output circuitry while increasing performance. The volume control is a single stage instead of two stages and has more range; it is quieter and more accurate. This is the same volume control as used in the XP-30. Overall this makes for a quieter, more neutral, musical, and versatile control center for your system. The XP-22 measures spectacularly well — but it really stands out sonically.