PS Audio HCA-2 power amplifier Robert Deutsch, January 2006

Robert Deutsch wrote about the HCA-2 in January 2006 (Vol.29 No.1):

PS Audio's HCA-2 power amplifier was originally provided to me as a companion to their PCA-2 preamp, which I was set to review. That review was abandoned when we got word that PSA's preamps and amps were about to be completely revamped using the Gain Cell technology, which would make the review out of date as soon as it appeared. I'd grown quite fond of the HCA-2 in my casual listening, and I was interested in how it would compare with the PS Audio GCC-100. To keep things on as level a playing field as possible, the HCA-2 was, like the GCC-100, plugged into the PS Audio P500 Power Plant; and, as is my standard practice, all direct comparisons were level-matched to within ±0.2dB (measured with a voltmeter at the terminals of my Avantgarde Uno speakers).

The most immediately obvious difference between the HCA-2 and the GCC-100 was the HCA-2's higher noise level. Not much higher, and not apparent at all when playing music, but with nothing playing and the volume set to produce the same relatively high level, I could hear it at the listening seat. The GCC-100 was definitely quieter.

The sound otherwise had a family resemblance, being smooth and neutral in tonality, but the HCA-2 did not have quite the GCC-100's degree of transparency, and the soundstage was not as clearly defined or as wide. I can't say whether the GCC-100's superiority is due to the Gain Cell, the redesigned output stage, or both; in a sense, it doesn't really matter. The most important thing is that, as an amplifier, the GCC-100 represents an advance on the Class A–rated HCA-2.—Robert Deutsch