Herron Audio M150 monoblock power amplifier Page 3

But let's go back to the positives I heard from the M150s that first time in Las Vegas and in every listening session at home: The amplifiers were superbly well organized in time. They were rhythmically coherent, creating a correct sense of musical organization. And yes, they were "liquid," sounding neither "tubey" nor "solid-state." I have to agree with Herron's assessment of his amplifier: To me, it sounded remarkably neutral tonally and harmonically, extremely well-focused without etch or grain, and offered the low-frequency control of a good solid-state amp and the smooth, liquid detail of a good tube amp. He's accomplished all of that, and that's a great deal. Mel at Marty's may not have had "legs" to stand on, but the rest of the presentation was superbly neutral, detailed, and honest...though I've had a greater sense of being able to reach out and "touch" the performance with other amplifiers in the same system.

Details Galore
The Herron M150s reminded me of the Infinity Prelude loudspeakers I reviewed in the May 2000 Stereophile. Infinity worked hard to create a truly "flat" loudspeaker by eliminating "peaky" tweeter performance; the result was a smooth-sounding speaker that initially sounded as if it didn't really have extended highs or a great deal of detail. In fact, the Prelude had both, as did the Herron monoblock. Extended listening revealed that the speaker's top end was airy and extended, and the flatness of the response revealed incredible inner musical detail, especially among different instruments inhabiting a similar frequency band.

The Herron, like the Preludes, was designed to be listened into, not to blow you away in your seat. There was nothing sparkly or crystalline about the M150's high-frequency performance, nor was there anything dull, rolled-off, or muffled.

This self-effacing quality made the M150 less than the most exciting amplifier I've ever heard, but one that should satisfy many listeners over the long haul. It imparted very little of its own sonic character on the music, but most of the character that I did notice with any consistency was subtractive in nature. Sometimes I'd feel that the M150 shortchanged macrodynamics (it certainly got microdynamics correctly), but then I'd put on a record like Classic's 45rpm edition of Mussorgsky's Pictures at an Exhibition (Reiner/CSO), and the full orchestral slam was there. Whenever I started thinking the Herron lacked deep, authoritative bass, some familiar low note would come along, and there would be no doubt that the amp had dug down very deep while remaining extremely well-controlled.

But when there wasn't an obvious low-frequency fundamental, as in a bass-guitar line, I felt a lack of midbass presence. Perhaps that's what Herron calls "bloom," but I think it was part of why the soundstaging lacked "legs," at least in my room with the Amati Homages. And it may have contributed to the other subtractive qualities I consistently noticed: images, though solid, lacked body weight, and the soundstage always opened from the speakers back, never seeming to project forward into the room. As a friend put it, "You can't wrap yourself around the picture." Or sense that you can walk into it, as you can with some other amplifiers.

Nonetheless, the Herrons did produce an accurate soundstage in terms of depth and width—it's just that the picture never existed forward of a line drawn between the speakers, and that the overall picture was more compact than the one drawn by some other amplifiers. For better or worse, the Herrons' clarity laid bare with ruthless precision the microphone techniques used by many well-regarded engineers: clusters of musicians standing around microphones at Columbia's old 30th Street studio were exposed populating the soundstage of Duke Ellington's phenomenally spacious and well-recorded Piano in the Background (Columbia CS 8346, "six-eye").

Herron values lack of coloration over harmonic drama, and the M150 seemed to be colorless—a word that has both negative and positive connotations. On the positive side, it meant that the lack of vivid, additive colorations from the amp—which, while exciting in the short haul, can grate and bore over time—allowed the true harmonic makeup of instruments to shine through. I believe that the M150 is among the most neutral amplification devices I've yet encountered—I never could get a harmonic handle on its sound. On the other hand, I was seldom excited or enthused by what I heard. My response was more a consistent feeling of respect and appreciation for Keith Herron's clearly brilliant balancing act.

That may not be a bad thing. In fact, it had me thinking back to the time I spent with the pair of Audio Research VTM200s. These monoblocks got my adrenalin pumping with their big 3D images, dramatic soundstaging, and intensely dynamic swings...but I had trouble with their string tone. I don't blame Audio Research's Terry Dorn for saying, in his "Manufacturer's Comment," that I got that part "wrong"—he might be right—but it's what I heard.

String tone from the Herron amps was far more sonorous and liquid—and that's from a solid-state amplifier—but their overall sonic picture was far less intense, less transparent, and much less entertaining. Perhaps with that last comment I've damned myself as a seeker of sonic thrills. So be it. Perhaps all Herron is selling is "music." Perhaps, with my music, I want a roller-coaster ride.

Have you ever seen an unsure animal poking and prodding another one that's playing possum as a defense? That's how I felt during my months with the Herron M150s. It's quite possible that I listened right past one of the finest amplifiers ever designed and mistakenly heard one that's merely very, very good. I poked and prodded, but was never sure what I was hearing. The Herron M150s always delivered music, and without tacked-on glaze, glare, grunge, or too much or too little of anything. They never sounded bright, dull, rich, threadbare, compressed, weak, or strong. Was their tonal balance utterly neutral or utterly bland? I'm not sure, for while I always respected what I heard, I was rarely enthralled or moved. I was enthralled and moved by the music, but not by the amplifiers. Maybe that's more of an indictment of my listening preferences than it is of the amps' performance.

My only reservations were about the M150's subtractive qualities: Maybe it was a bit light in the midbass, or lacked natural, not artificial, bloom—but Keith Herron is anti-bloom, convinced that bloom isn't in the music and shouldn't be in the audio system. The M150 was about the most neutral amplifier I've yet encountered, and that's why I felt it was playing possum with me—I kept wanting for it to show its true nature. Perhaps, in its unwavering neutrality, it was.

Still, I was troubled by the M150s' lack of soundstage "legs," and by their self-effacing-to-a-fault, non-vivid overall presentation. I wanted more solidity and dimensionality, more balls. But amplifiers don't have balls—or breasts or butt cheeks, for that matter. We always say we want the electronics to get out of the way and let the music through. The M150s may very well do that better than any amplifier I've yet encountered. If so, I'm ashamed to say that, at the end of the day, that's not what I want.

Call me an "audiophile." In some circles, you couldn't call me worse! Perhaps the combination of the M150s and the Amati Homages was not a good one. Or perhaps Keith Herron has designed out more than just the colorations of most amplifiers. Maybe he's gone overboard and, in his desire to design out colorations, has designed out some of the life of recordings and music.

You'll have to be the judge of that—and I strongly recommend that you put on your black robe and find out. Don't let the M150's plain looks fool you: it's a special amplifier that deserves your serious attention.

Herron Audio
12685 Dorsett Road, #138
St. Louis, MO 63043
(314) 434-5416