Over time, reviewing the high end’s best power amplifiers has become increasingly more difficult, particularly those with solid-state output stages, high power and high current, and damping factors sufficient to help control a speaker—in other words, the kind that have become the norm for most audiophiles. Amplifiers seldom sound alike, but more and more, they differ only in more subtle nuances rather than in dramatic sonic differences.
In many cases, the nuances an audiophile actually hears also depend heavily on how revealing all the other elements—active and passive—in his or her system are. The sonic nuances of a whole high-end system are inevitably shaped largely by that system’s most colored components, as well as the interactions between a particular speaker and a particular listening room. As a result, these colorations and interactions will often mask many of the more subtle nuances in power amps.
What’s more, I find A/B listening tests to be an uncertain way (at best) to audition components. The colorations caused by other components, variable room interactions, and often the noise from other people, create too many masking effects and problems—as do short listening periods and any form of blind testing.
Understanding the nuances in given components takes time and patient listening to a wide variety of recordings and music. It is all too easy to become confused by switching too rapidly, hearing differences caused by unfamiliar recordings, and by minor shifts in loudness. (This is a reason why I strongly recommend working with the kind of dealer who will really let you listen, and possibly offer the loan of a really expensive amplifier so you can hear it in your system.) While some people talk about A/B testing as if it were a simple exercise, it is subject to all the problems that affect every aspect of any operations research that involves human testing—factors such as primacy and regency, focusing on the wrong variable, etc.
There also is no one right answer to choosing the best amplifiers; rather, it involves the sonic preferences that suit you and your particular system and room best. Today’s top designers and design teams—from legends like Nelson Pass, John Curl, and Bascom H. King to young Turks and collective design efforts—are producing a wide range of amplifiers that can present as musically realistic a sound as the recording and the rest of the components will permit.
Additionally, one must consider the specific variable qualities of music reproduced through a high-end system, including timbre, soundstaging and imaging, dynamics, and musical contrasts. Your listening position also impacts what you hear. Similarly, these same sonic aspects differ across various positions within a concert hall. No two venues or collections of instruments sound exactly alike, and every known brand of microphone and every other stage in the recording process has colored the music to some degree even before you begin the playback process. Ultimately, the key question is never, “What is truth?” It is rather, “What is the most satisfying and seeming realistic illusion of music?”
Enter the PS Audio BHK Signature 300
And yet, some amplifiers really are distinctive successes, and the PS Audio BHK Signature 300 monoblock is definitely one of them. Its BHK namesake references the amp’s designer—one of the audio legends I mentioned above—Bascom H. King’s initials. The BHK Signature 300 also reflects the deep involvement of PS Audio founder Paul McGowan and Arnie Nudell, who headed Infinity when it was one of top speaker firms in the world, and here served as a key listener.
This amplifier isn’t cheap, although it represents a bargain in sound quality compared to all too many of its higher-priced competitors. A pair of BHK Signature 300 monoblocks costs $14,998, and a BHK Signature 250 stereo amplifier costs $7499. Top-of-the-line prices should mean exceptional sound, and any amps that are not truly exceptional at any comparable or higher prices are simply a rip-off.
You do, however, get your money’s worth with the BHK Signature 300s. They have truly exceptional imaging, depth, and natural soundstage width, and they really can get the best out of the naturally miked and produced recordings that have a real-world soundstage. Once they are broken in, they have very little sound character of their own, but to the extent they do, they have a rich, natural musical timbre without any loss of highs or air.
The 300s’ dynamics are extraordinary, particularly in the lower octaves that seem to be in even more demand for audio reproduction today than the upper octaves (higher levels) that had previously been the key design challenge—until great performance at high powers became the rule, rather than the exception. Bass goes as deep as your speakers will permit. The amp’s control with difficult speaker loads is excellent, while the upper bass and lower midrange—which dominate most actual musical sound—have no touch of leanness or lack of natural warmth.
This performance is not simply a matter of power or “watts,” although the BHK Signature 300s are scarcely shy in this regard. They provide 300 watts minimum into 8 ohms, 600 watts minimum into 4 ohms, and 1000 watts into 2 ohms. They can drive a friend’s early Apogee speakers—candidates for most demanding speaker ever made. They handled both my Wilson Alexias and Spendor BC-1s with ease—both loads that aren’t that easy by any standard. In fact, the Signature 300s did better with demanding dynamic passages and sudden sharp musical contrasts than an amp rated at 600 watts.