Tube Power Amp Reviews

The album I always played for visitors was a spectacular reissue of Aaron Neville's 1991 breakout solo album, Warm Your Heart (2 45rpm LPs, A&M/ORG 141), coproduced by Linda Ronstadt and George Massenburg. The reaction to "Everybody Plays the Fool," even from hardened audiophiles, was always visceral and accompanied by "Oh wow!"s as the amps produced a soundstage limitless in width and depth, on which three-dimensional instruments, both acoustical and synthetic, appeared out of pitch blackness. Neville's voice—vividly drawn, free of artifacts, and 3D—hovered in space well in front of the plane described by the speaker baffles.

From the sidelines, I watched as listeners' eyes widened in surprise, their heads responding to the array of instruments-liquid and solid, airy and dense, cool and warm-spread across the wide, deep expanse. Larry Klein's bass may have been written a touch too large, but a "touch" is more than a worthwhile trade-off for the Lamms' bass liquidity and effortless textural density.

And I'll throw in a plug for the Wilson Alexandria XLFs. Drivers plastered to a baffle, even an angled one, don't, in my experience, produce the kind of seamless, three-dimensional, "baffle-free" presentation managed by the XLFs, even when I sat less than 10' from them. If other speakers manage that, I'm still waiting to hear it.

Yes, obvious choices produced the expected sonic glories through the ML3s: an original shaded dog of Schubert's String Quartet 14, "Death and the Maiden," with the Juilliard Quartet (LP, RCA Living Stereo LSC-2378); Johanna Martzy's performances of J.S. Bach's Sonatas and Partitas for Unaccompanied Violin (EMI/Electric Recording Co.); an original pressing of Elgar's Cello Concerto with Jacqueline Du PrÇ, John Barbirolli, and the London Symphony (LP, EMI ASD 655); and a superb reissue of Nick Drake's Pink Moon (LP, Island/UMG). But so did unlikely ones, such as the Rolling Stones' Tattoo You (LP), in which Keith Richards's rhythm guitar chimed and shimmered—almost as well as it did a few days later, when I saw them live in Philadelphia.

Of course, Roy Orbison and Elvis Presley sounded amazingly lifelike, as did Ella Fitzgerald and Sarah Vaughan, but Never Mind the Bollocks, Here's the Sex Pistols (LP)? Yes. No problem. The Clash's London Calling (UK LP, Columbia)? All the guitar bite you could want, reasonably taut bass lines, and dynamics sufficient to sell the package. The solo acoustic guitars of John Renbourn and Bert Jansch? The ridiculously fast Lamms produced lifelike transients, but not at the expense of nuanced attacks.

Nor did the ML3s shy away from large-scale symphonic works. Mahler's Symphony 2, with Andrew Litton conducting the Dallas Symphony Orchestra (CD, Delos 3237), produced enormous and, more important, realistic dynamic swings. A disc of Beethoven overtures, with Colin Davis conducting the Bavarian Radio Symphony Orchestra (SACD/CD, Columbia Masterworks/TEAC Esoteric), was both dynamically assured at both ends of the scale and tonally rich, the horns sounding particularly full-bodied and the spatial contours of Munich's Herkulessaal expressed so convincingly that I thought the 2x4s framing my room might snap (okay, I'm exaggerating).

Rough Mix
When John Atkinson dropped by to pick up the Lamms for measurement, he brought with him a rough mix of two tracks he'd recorded of Bob Reina's group, Attention Screen, performing in a Queens church. I attended that concert, and wrote about it in this issue's "Analog Corner" column. We played the 24-bit/88.2kHz files through the recently arrived dCS stack of Vivaldi DAC, upsampler, and word clock, and the ML3s well reproduced the church's moderately sized sanctuary and the music's wide dynamic swings. I felt almost as if I were back in the room.

One piece, a Pat Metheny-like composition by bassist Chris Jones, features a most delicate bell-like, percussive chime produced by one of the refurbished organ's stops, along with a delicate organ fill by Bob, and trumpeter Liam Sillery, whose part carried the melancholy melody.

The chimes sounded remarkably lifelike—as I heard them that day in a mid-church pew—while Jones's double bass was slightly less solid and less well controlled than I remember it sounding live, with the instrument and the reverberant space more blended and less well-separated.

The Lamms gone, I reconnected the big darTZeel NHB-458 monoblocks ($144,500/pair) and, after letting them warm up for a day, played the track again. Through the solid-state amps, the sprinkly chime was still fast and precise but somewhat more harmonically reserved, and less three-dimensional and lifelike. But the double bass was definitely more like what I'd heard live, with greater control and authority, a tighter physical presence, and better delineation of the instrument from the reverberant space. All of which was also true of the trumpet: a bit less bloat, but a slightly drier sound. The hall and the instruments in it were also pushed somewhat farther back from the listening position than they were through the Lamms.

A strong case could be made for the verisimilitude of the sound from either of these pairs of similarly priced amplifiers, but the award for mesmerizingly hypnotic sound must go to the Lamm ML3 Signature. Whatever your system, this Attention Screen concert is going to make a great CD that I hope will also be available as a high-resolution download.

Feedback and Taps
Whatever JA's measurements reveal, I found that the ML3's 4 ohm taps produced the greatest dynamics and effective speaker coupling. I also experimented with the two feedback switches designed to lower the output impedance. Theoretically, they should tighten the bass and produce somewhat more linear performance, but I found that while both feedback settings did somewhat tighten the bottom end, they also reduced the ML3's most attractive spatial and textural qualities, at the same time diminishing overall purity.

The Epitome of Tube Sound?
The only other assault on the state of the art of tubes that I've heard at home was the big, four-box, WAVAC SH-833, which I reviewed in the July 2004 Stereophile. The ML3s are easily within reach of anyone who'd buy the WAVACs (they cost $350,000/pair at the time), with plenty of change left over to pick up Ferrari's least expensive model. I reread my review to refresh my memories of the SH-833's sound.

Despite the SH-833's rated "effective" output of 150W, it put out 2W or less at Stereophile's definition of clipping: 1% THD+noise. That's pants-down performance! Lamm claims 0.3% THD at 1W into 4, 8, or 16 ohms—or 32W at 3% THD, which is three times our definition of clipping. If the ML3s can produce 12W at 1% THD, that's probably more than twice as much power as is needed to drive the Alexandria XLFs to very high SPLs in my room. Which is how it sounded.

I heard excessive warmth from the WAVACs, and JA was able to measure and explain why. The ML3s sounded far more linear overall, especially at the bottom, though not as linear or as well controlled as the darTZeels, but it was close enough to call it a trade-off: the tube amp provided greater textural and harmonic detail and, especially, a more fully fleshed out midband; the solid-state amp provided greater bass control and dynamic thrust, and a bit more extension.

No doubt the Lamms will measure less well than the darTZeels but much better than most other SET amps. That said, the darTZeels didn't measure as well as some other solid-state amps, but they sure sounded a hell of a lot better than most I've heard.

Conclusions
Cost and value for money aside, the Lamm Industries ML3 Signature is among a handful of the most pleasurable-sounding amplifiers I've ever heard. They produced magic with every listen, without glossing over or homogenizing the faults of poor recordings. While sounding as good as they probably ever will, those recordings still sounded bad-but great recordings were flat-out overwhelming.

The ML3s produced the most glorious, palpable, airy, detailed midrange I've ever heard from reproduced music. That part is easy. They pushed that performance envelope without going all greasy and congealed over time, as some tube amps do after the initial appeal of warmth wears off.

The ML3's standout features were its natural re-creation of instrumental attacks, generous sustain, and lifelike decay—all as close to live as I've heard, if nowhere near the real thing. It was quiet, fast, detailed, dynamic without reservation, transparent, airy, and extended on top. No sharp edges unless the recording had them, and no boredom-inducing global softening. The pair of them produced an enormous sense of space when that was appropriate, and, within that space, images of exceptional delicacy, three-dimensionality, and body.

The ML3's sonic consistency from top to bottom of the audioband and in every performance parameter, and its freedom from obvious sonic artifice, helped produce an illusion of live music as have few amplifiers in my listening experience. Nonetheless, the gulf between solid-state and tube amplification remains, along with the trade-offs unavoidable with either technology, though those are diminishing over time. If you want full weight and articulation on bottom, especially if you listen to a lot of electronic and/or amplified music, you'll probably be on the solid-state side of that gulf. But Lamm's ML3 Signature makes the case for tubes better than any other amplifier I've ever heard.