The New Pass Labs’ HPA-1 Headphone Amplifier  was designed on a “clean sheet of paper” as though it were to be used as a power amplifier.

The HPA-1 Headphone Amplifier is capable of driving difficult loads in terms of impedance, power consumption or both and it has been designed as a real Class-A power amplifier in its own right.

The foundation of the HPA-1’s engineering is a custom, low-noise shielded toroidal power transformer feeding a discreet low noise regulated power supply for the audio circuits.  The HPA-1’s amplifier circuits are low-feedback, wide-bandwidth discreet designs employing a J-Fet input stage and a Mosfet output stage biased into Class A-biased direct-coupled output stage.

The HPA-1 has a single headphone jack on its front panel, two sets of single-ended analogue inputs via RCA jacks on the rear panel, and also a set of switchable “Preamp” line-level output jacks on the rear panel.  The HPA-1 can be used as a stereo preamp. The rear panel holds the power switch and fuse. Volume control is via a hefty rotary knob connected to an ALPS Potentiometer. The other front-panel controls are three pushbuttons, to select inputs or to engage the Preamp output.

Price $3500