Pass Labs HPA-1 Class A Headphone Amplifier Now Available

Following its first presentation at CES 2015, Pass Labs has now confirmed availability for its highly anticipated new headphone amplifier. The HPA-1 is able to drive headphones presenting loads from 15 to 600 Ohms. It features a custom shielded toroidal power transformer feeding a discreet low noise regulated power supply, J-Fet input stages and Class A-biased direct-coupled MOSFET output stages.

Over the years, some of the best Nelson Pass projects have been featured by Audio Amateur and audioXpress magazines. The A40 power amp article was published in The Audio Amateur, 4/78, and the A75 power amplifier appears in The Audio Amateur 4/92 and 1/93. His other works are posted at passdiy.com. Originally published by audioXpress on May 2010.