Pass Labs’ new HPA-1 headphone amplifier is said to be “capable of delivering full-range dynamics across the entire frequency range, even when driving headphones that present difficult loads in terms of impedance, power consumption or both.”
The HPA-1 was designed as a Class-A power amplifier that cuts no corners in circuit design and omits unnecessary frills. And naturally no necessary expense has been spared in its execution. The HPA-1’s features a custom, low-noise shielded toroidal power transformer feeding a discreet low noise regulated power supply for the audio circuits. The importance of the power supply is often overlooked in more affordable amps and plays a large part in overall performance. The HPA-1’s amplifier 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 easily drives headphones presenting loads from 15 to 600 Ohms, particularly excelling on planar headphone designs.
The HPA-1 has a single high-quality headphone jack on its front panel, two sets of single-ended analog inputs via RCA jacks on the rear panel, and also a set of switchable preamp line-level output jacks on the rear panel. There are no compromises with the HPA-1 when used as a stereo preamp and it will compete against contemporary preamplifiers. 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.
The substantial casework is the customary and well-recognized brushed aluminum shared with other Pass Laboratories products. Dimensions are 4.5” H x 11” W x 13” D; weight is 14 lbs. The HPA-1 is available now at US MSRP $3,500.