MBL 6010 D Preamplifier

Equipment report
Solid-state preamplifiers
MBL North America 6010 D
MBL 6010 D Preamplifier

Since I plan to compare the MBL 6010 D linestage preamplifier—the big brother to the 5011 that Wayne just extolled—with the best tube preamplifier I’ve heard, the Audio Research Corporation Reference 3 (reviewed in TAS 159), I want to start by talking a bit about tubes and transistors.

In our next issue, reviewer Jacob Heilbrunn notes that the twain shall never meet, and he’s right. The trouble is he’s also wrong. The two don’t sound more alike in important specific ways, but they do sound more alike in important general ones.

Let me explain. If you were to map the anatomy of a musical note, it would divide neatly into three sequential parts or phases: the attack or transient phase, the steady-state tone phase, and the decay phase. All three are essential to creating a lifelike semblance of the real thing, but all three are more or less fudged by both the recording and playback process.

What typically goes wrong, to my ear, is something that might be called “timing errors”—that is, errors in the realistic reproduction of the duration of each event (and each event has a different duration). As jitter does in digital recording and playback, timing errors in analog recording and playback tend to distort—to artificially expand or condense—the little slices of time (and the dynamic/harmonic information that is contained in them) that constitute each phase of a note’s sound.

Typically tube playback makes everything sound “longer,” like the sostenuto pedal on a piano— i.e., it expands a note’s duration, enriching its colors and textures but softening its impact. Harmonics seem to linger in the air longer with tubes; the air itself seems to be more present; instruments seem larger and more forward on the soundstage. At the same time the sharpness of instrumental attacks seems slightly dulled—too spread out over time. Consequently, instrumental outlines are more splayed out and fuzzier, bigger and less focused.

Typically solid-state playback makes these same events sound “shorter,” like the damping pedal on a piano—i.e., it condenses a note’s duration, slightly desaturating tone color and abbreviating slow-developing textures, but increasing clarity and focus in the way that the clean sharp lines of a penand- ink drawing do compared with the thicker, softer lines of a pencil sketch. Harmonics don’t seem to be as richly developed as they are with tubes; the sense of air around each note (and of air expanding and collapsing with the building up and decaying of dynamics and tone—what I call “action” or “bloom”) is lessened; instruments seem slightly smaller, more focused, and less forward on the soundstage. At the same time the sharpness of both starting and stopping transients is enhanced; consequently, instrumental outlines are sharper and more distinct, and large-scale dynamics have greater and more lifelike speed and impact.

To put this difference more positively, transistors are faster on the uptake, and better at reproducing that part of the note where speed and concision matter most—the attack or transient phase. Tubes are slower to start, and better at reproducing those parts of the note that develop more gradually over time— the steady-state tone and decay phases. Both gain strategies have trouble shifting speeds, and even at their best both only approximate the actual durations of real-life musical notes.

This is the way things stood until fairly recently. Yeah, some solid-state had begun to slow down enough to let you smell the roses; and some tubes had gained significantly in transient speed and clarity. But, as Jacob correctly notes, the fundamental virtues (and vices) of tubes and solid-state have remained more or less the same.

The arrival of the MBL 6010 D preamp and MBL 9011 amplifier, followed shortly thereafter by the Audio Research Reference 3 preamp and Reference 210 amplifier, shook my faith in this paradigm. Not that you would mistake the sound of MBL for ARC; they both still shine where transistors and tubes customarily shine. The thing of it is they also shine where transistors and tubes customarily don’t.

Although I’ve already used this musical example in my review of the ARC Reference 3 and Reference 210, it is worth repeating because it so clearly points up the difference between the MBL 6010 D and every other preamp I’ve heard.

Towards the end of the first movement cadenza in Montsalvatge’s Concerto Breve for piano and orchestra [London], pianist Alicia de Larrocha plays a loud chord sforzando (i.e., suddenly and forcefully) and then uses the sostenuto pedal to sustain the harmonics. The note goes on for several seconds, and at its finish, after each of the piano’s tone colors has died away, a single very-low-level enharmonic overtone continues to sound for a time before it finally and unmistakably stops, and the note ends.

This is a classic example of instrumental decay—the lowlevel harmonic and dynamic information at the tail end of a note. In this case, decay is more marked because of the use of the sustain petal and the moment of rest that follows it, but in general it holds to the outline of any instrument’s decay.

In the past, tubes have been the indisputable champs of decay, and of very low-level resolution of tone color and dynamics. Even though they are often noisier than solid-state, they still hold onto notes longer, spinning them out more fully than transistors do.

With the MBL 6010 D, this paradigm was, for the first time, turned on its head. No other preamp that I’ve heard can clearly and audibly sustain Alicia de Larrocha’s sostenuto (or preserve something like the back-of-the-stage echo of Ian and Sylvia’s voices on the “Texas Rangers” cut of Northern Journey [Cisco/Vanguard]) as fully and completely as the 6010 D—not even the great (and it is) Audio Research Reference 3. As I’ve already noted, listening through the ARC Ref 3, you would be hard put to decide exactly when that piano note ends and silence begins; the sound just sort of dithers away into the slightly higher noise-floor of the tube preamp. With the 6010 D, the end of that note is like a bank vault door closing.

Nor does the 6010 D’s uncanny grip on the timing of notes just apply to decays. It does timbre (the steady-state tone phase) with astonishing richness, and, of course, it retains solid-state’s superb transient response on the attack phase. The net result of the MBL’s very low level of “timing error” is a huge increase in resolution with few or none of the usual solid-state penalties paid in the desaturation of tone colors and loss of fine textures. The 6010 D is the highest-resolution preamp I’ve yet heard— and, simultaneously, the least analytical sounding. In fact, it is downright gorgeous.

The truly wonderful thing about having all this beauty, energy, and resolution on tap is how much the 6010 D can tell you not just about where, when, and how individual instruments are being played, but also about the way in which an entire piece of music is designed to work. By so clearly preserving the timing of the dynamics and harmonics of pianist Robert Miller’s Steinway in Mario Davidovsky’s Pulitzer Prize-winning Synchronisms No. 6 [Turnabout], for instance, the 6010 D makes it plain that the composer is consistently using Moogsynthesized sounds to modulate the piano’s attacks and decays. Likewise, when composer Luciano Berio has violinist Romuald Tecco sound a quarter-tone to make a brief surprisingly askew harmony with Dennis Russell Davies’ piano in “Due Pezzi” [Philips], the 6010 D’s uncanny way with this “bent” note’s color and duration gives you a crystalline sense of the Bartókian wit of the piece—and of the virtuosity with which Berio typically writes for individual instruments.

What is the reason for this sudden increase in solid-state resolution, particularly with longer-duration events, like the build-up and decay of timbre? HP has recently argued that the improved resolution of the best gear is due, across the board, to a significant lowering of the noise floor. However, I’m not certain that the 6010 D’s very low noise and very high bandwidth are all that make it such a standout, although I am sure that these things contribute greatly to its excellence.

MBL makes a big deal about the quality of the 6010 D’s power supply (so, BTW, does ARC with its Reference 3), and I’m inclined to think that, in both instances, power supply is the key. Part of the difference between solid-state and tubes— part of the reason for their characteristically different timing errors—is the speed with which they dispense their energy. With their quicker rise times, solid-state preamps and amps were always better at events that called for sudden bursts, like transients or big dynamic swings, and because of their advantage in bandwidth this inherent speed was also available at the frequency extremes. The “slower,” more bandwidth-limited, but more continuously available power (because, unlike transistors, tubes have no on-off cycles) of tube preamps and amps made them better at providing energy for slower-to-develop, longer-duration events, like the buildup and decay of timbres.

This has now changed. It’s as if the MBL 6010 D has not only much greater reserves of power on tap, but it has also developed another gear—a sostenuto pedal of its own, if you will— so that it no longer treats everything like a transient and, thereby, shortchanges the development and decay of timbre. At the same time, it is also fair to say that the ARC Reference 3—with its greatly improved bandwidth, lower noise floor, and significantly beefed-up power supply—no longer blunts starting transients to the extent that tubes once did; nor is it anything like a slouch at the frequency extremes. While not quite the inexhaustible dynamo that is the MBL 6010 D, the Ref 3 comes surprisingly close to that new paragon (closer, actually, than I gave it credit for when I reviewed it), and exceeds the 6010 D in certain important respects (for which, see below).

So is the MBL 6010 D the “perfect” preamp? While it comes closer to these laurels than anything else I’ve heard, no, it is not.

First, it is persistently a bit darker and prettier than life. I doubt if either of these colorations will bother anyone much, but, for the record, they are there.

Second, while it has more detail overall than anything else out there, some information escapes it. Here we come, again, to the classic tube/transistor crossroads. The 6010 D cannot be beat from the plane of the instruments—which, characteristically with the MBL, are set back a bit in the soundstage—to the rear walls of the hall or studio. It will reproduce any musical event that occurs in this portion of sonic space more fully than any other piece of electronics I’ve heard in my home. But…from the plane of the instruments forward to the listener, the Audio Research beats it out.

What I am referring to here is the way instrumental voices are projected towards you and recede back as dynamics build and wane—what I call action or bloom. The MBL 6010 D is certainly not devoid of bloom, but compared to the ARC it is just a bit more static in imaging, where the tube preamp is alive with the ebb and flow of musical energy.

Third, the MBL’s soundstage depth and height are terrific, but its stage width seems just a tiny bit narrower or, at least, more compacted than the ARC’s. This is probably a psychoacoustic effect, because the ARC is a somewhat bigger imager than the MBL and not as dark or warm as the 6010 D, and the air between and around instruments is therefore easier to sense.

The difference between the sound of these two preamps is actually small but profound: The MBL 6010 D reproduces LPs and CDs in a way that seems to take you to the recording site— with it you are there in the studio with the musicians. The ARC Reference 3 reproduces LPs and CDs in a way that seems to bring the instruments from the recording site into your home—with it the musicians are there with you in your room.

Which presentation do I prefer? Well…that depends on my mood. For the greatest transparency to the source, for that time-warp feeling of being an eavesdropper at the recording session, the 6010 D is nonpareil. For the greatest life-likeness, for that chill-up-the-spine sense of hearing instruments sound as if they are in the room with you, the ARC Reference 3 is marginally superior—but only marginally. Frankly I can live more than happily with either preamp—and do. (I should note that the 6010 D gives you the option of a solder-in phonostage board that is as good as anything short of top-line stand-alone phonostages like the Lamm, Aesthetix, ARC, or ASR. The ARC does not have this built-in phonostage option.)

Of course, if you want to get a taste of both contemporary solid-state and tube strengths, just use the old-tried-and-true method of pairing the 6010 D with the tube Reference 210 (or the ARC Ref 3 with the solid-state MBL 9008); I’ve heard both mix ’n’ match combos, and they sound fantastic.

MBL North America, Inc.
(212) 724-4870
[email protected]