Solid State Power Amp Reviews

One of the highlights of recent Consumer Electronics and Home Entertainment shows has been the demonstrations of sound quality put on by Australian amplifier manufacturer Halcro with Wilson Audio loudspeakers. At my first exposure to one of these demos—described in my April 2002 "As">http://www.stereophile.com/asweseeit/557">As We See It"—enormous dynamic range was coupled with a grain-free presentation and almost holographic stereo imaging to produce a breathtaking sweep of sound. Paul Bolin reviewed Halcro's dm58">http://www.stereophile.com/amplificationreviews/683">dm58 monoblock in October 2002, and that amplifier was subsequently voted this magazine's "Amplification">http://www.stereophile.com/features/724/index2.html">Amplification Component of 2002" by our reviewers.

Without passion man is a mere latent force and possibility, like the flint which awaits the shock of the iron before it can give forth its spark.—Henri-Frédéric Amiel

It's true—you never forget your first love. And no, I'm not talking about little Jackie Lynn Neeck in my second-grade class when I was seven years old. I still remember her, almost as vividly as I remember my first encounter with a fantastic stereo system, and therein hangs a tale.

Consider the plight of solid-state muscle amps. Often derided as brutes lacking sophistication or subtlety, particularly by the SET set (ie, fans of single-ended triodes), these powerhouses are taken for granted and often, like Rodney Dangerfield, they get no respect. And once upon a time, the stereotypes were true. Every veteran audiophile has at some time heard an immensely powerful transistor amp that had the soft sonic allure of a sheet of sandpaper, a lumbering oaf of a component with nothing whatsoever to recommend it save for a bulging set of mighty moose muscles.

Pass Laboratories' X amplifier series represents the efforts of designer Nelson Pass to prove that simple linear amplifier topologies can be scaled to provide high-quality audio performance at very high power levels. The handsome X1000 monoblock under scrutiny here, the largest and most powerful amp in the Pass stable, makes 1000W into 8 ohms and a mighty 2000W into 4 ohms. The amplifier has no global negative feedback, and only two gain stages: the front-end provides all the voltage gain and feeds a high-current follower stage.

As technology develops, things get more and more complicated. With every update of Windows, the program offers greater flexibility, but runs slower and makes greater demands on hardware. Automobiles have become so complex that only the most highly trained mechanics are able to fix even a minor malfunction. Surround-sound processors come with inch-thick owner's manuals.

For me, the iconic Adcom power amplifier was the GFA-555. As an aspiring audiophile, I was deeply impressed with Tony">http://www.stereophile.com/amplificationreviews/678">Tony Cordesman's review in Stereophile in 1985 (Vol.8 No.4). That did it! After years of kit-building and doing it myself, the '555 was the first factory-built amp that I wanted and could afford. Over the years, I changed speakers several times, and even added a fully regulated power supply to the '555, but it never balked. At the end of its tenure at my house, it had been demoted to my third-string backup; today it's making someone else tap his toes.