PS Audio GCC-100 integrated amplifier:
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Although PS Audio insists that the GCC-100 is not an integrated amplifier, it has an Auxiliary line-level output—just like an integrated. The Auxiliary output can be used to drive another power amp, connecting the speaker cables to that amp rather than to the GCC-100, in which case the GCC-100 functions essentially as a line-level preamp. (Leaving the output/amp section of the GCC-100 without a speaker load is apparently not a problem.) I used this connection to compare the GCC-100's output/amplifier section with two other amplifiers I had on hand.

Comparisons: HCA-2
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PSA's preamps and amps were about to be completely revamped using the Gain Cell technology, which would make the review out of date as soon as it appeared.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 GCC-100. To keep things on as level a playing field as possible, the HCA-2 was, like the GCC-100, plugged into the 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 speaker terminals).

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.

Comparisons: Audiopax Eighty Eight
The second power amp I had around for comparison was the Audiopax Model Eighty Eight SE, a tubed single-ended pentode monoblock ($10,000/pair) that simulates the sound of single-ended triodes but with more power (see my review in the May 2003 Stereophile, Vol.26 No.5). The relationship between the sounds of the Audiopax and the Avantgarde Unos is a particularly synergistic one—in fact, the Audiopax was originally imported by Avantgarde USA because of that synergy. Again, to control potentially confounding variables, I had both the GCC-100 and the Audiopax plugged into the P500 set to its TubeWave setting, which is optimized for tube equipment but is also fine for solid-state.

The comparison between the GCC-100 and the Audiopax was fascinating, and highlighted the longstanding argument among audiophiles about "accuracy" vs "musicality." First the basics: The GCC-100, used as a line-level preamp, had no trouble driving the Audiopax. The noise level of this combination was much higher than that of the GCC-100 alone, but almost all of the noise was created by the Audiopax—muting the PSA or switching it to another input had virtually no effect on the noise. This was surprising to me, in that when I reviewed the Audiopax I'd remarked on how relatively quiet it was. I can't account for the difference, other than to say that it may have been due to some sort of ground loop. (I tried some other connections, but with no success.) In any case, in normal listening the noise was apparent only between tracks.

In general terms, both amplifiers were detailed and transparent, with fundamentally neutral tonal presentations. The GCC-100 clearly had greater top and bottom extension and was more obviously dynamic, sounding superior on large-scale orchestral recordings. However, the Audiopax was ahead in its ability to present music in a way that seemed to reduce the electronic artifacts of the recording/playback process, and in its ability to present voices in a way that had a more convincing in-the-room quality. You might say that through the Audiopax recordings sounded "better than they are," whereas the GCC-100 was more "Just the facts, Ma'am."

The original cast recording of Wicked (CD, Decca B0001682-02) was one of my 2005 "Records To Die For" selections (it also won a Grammy), and I consider Stephen Schwartz's score to be the best that Broadway has produced since Ragtime. Idina Menzel (see my interview with her in the December 2004 issue) as the not-so-wicked witch of the title is an enormously talented performer, and despite having listened to her rendition of "The Wizard and I" dozens of times, it still brings tears to my eyes. With the speakers driven by the GCC-100, the vocal and emotional power of the performance was there in full force, but when I changed over to the Audiopax, Idina just seemed more in the room, and the recording sounded less like a recording and more live.

To put this difference in context: The Audiopax does this better than any amplifier of my experience, and the respective costs are vastly different. It's also important to note that the preamp (Gain Cell) section of the GCC-100 was not at all outclassed in the pairing with the Audiopax—in fact, its performance made me think of investigating PS Audio's latest preamps, for which optional high-current power supplies are also available.

Est! Est!! Est!!!
It must have been nearly 20 years ago—definitely before I started writing for Stereophile—that I almost bought a PS Audio preamplifier. It was recommended to me by a dealer who said that it had no real competition at the price. I had one at home for a weekend, but in the end I went for a tube preamp, which seemed to provide a better match to the rest of my system. Over the years, I have often thought of that preamp (its model number may have been 5.5) and wondered if I made a mistake. Twenty years is a long time for an auditory or any other type of memory, but I still remember the pristine clarity of that preamp's sound.

The GCC-100 kept reminding me of that. Putting aside feelings of nostalgia—which, as we all know, is not what it used to be—the GCC-100 is a superb-sounding product that features the latest technology and a great deal of original thinking, at a price that represents an even greater bargain than that PS Audio preamp of yore.

As normally used, the GCC-100 is an integrated amplifier and performs exceedingly well as such, but it's really two other products as well. It's technically a variable-gain power amplifier, which means that it can be used as a power amplifier, driven by an outboard preamplifier or surround preamplifier-processor. To do this, you just set the GCC-100's volume control at 70, and the GCC-100 is then identical in performance to the fixed-gain GCA-100 amplifier. Alternatively, if you have an amplifier that you like more than the amp section of the GCC-100, you can use the GCC-100's Auxiliary output to drive that amplifier, the GCC-100 then functioning as a line-stage preamplifier. Owners of certain tube amps may want to follow that route, perhaps using the GCC-100 as the bass amp in a biamped system. Or, after having tried all the various configurations, you may just decide that the best sound is obtained by the GCC-100 on its own.