PASS Laboratories, renowned for its pre- and power amplifiers, now steps out into headfi territory with the HPA-1 headphone amp, which the company describes as a “class A-biased, fully-discreet, direct-coupled Mosfet output design.” But no, this is not aimed at the computer audio or mobile crowd – it’s all-analogue.
The HPA-1, designed ground up as “though it were to be used as a power amplifier”, is touted as capable of delivering full-range dynamics across the entire frequency range, even with headphones that present difficult loads.
The headphone amp is engineered around a custom, low-noise shielded toroidal power transformer that feeds a discreet low-noise regulated power supply for the audio circuits.
The circuits are low-feedback, wide-bandwidth discreet designs employing J-Fet input stages and Class A-biased direct-coupled Mosfet output stages. The HPA-1 is capable of driving headphone loads of 15 to 600 Ohms, and is claimed to excel with planar designs.
A single high-quality headphone jack is provided on the front panel, and two sets of single-ended analogue RCA inputs on the rear; there’s also a set of switchable preamp line-level output jacks on the rear panel. Pass Labs claims that when used merely as a stereo preamp, the HPA-1 will compete against contemporary preamplifiers.
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.
The casework is made from brushed aluminium and shares visual cues with other Pass products. Dimensions are 4.5 x 11 x 13 inches (h/w/d) and weight, a substantial, 6.3kg.
The HPA-1 is available now at US$3,500.
