Solid State Power Amp Reviews

I still remember reading about my first Mark Levinson product 14 or 15 years ago. It was a preamp. The model number escapes me, but it sold for over $2000. It was soon followed by the JC-2, designed by John Curl, which was a bit less pricey but still astonishingly expensive for a mid-'70s preamp. We've come a long way since then. The man, Mark Levinson, left the company that bore his name in the early 1980s and founded a new company, Cello. The company Mark Levinson became the core of Madrigal. It is a mark of their continued dedication to uncompromising high-end products that their bread-and-butter line remains the high-priced Mark Levinsons. They no longer have the Rolls-Royce of the audio market to themselves (in their early years, they made the never exactly inexpensive Audio Research products—ARC was certainly a contender for the same title—look like bargains), but they are certainly a leading player.

The Mark Levinson No.29 ($2800) is Madrigal's lowest-powered, lowest-priced amplifier. Externally, it resembles their other power amps, though the huge heatsinks of the larger designs are missing—shrunk dramatically in size and banished to the inside of the chassis since they have an easier job to do with this 50Wpc design. The only features of note visible on the outside, aside from the obvious power switch front and center, are the rear-panel jacks and fuses. The former include both balanced and unbalanced inputs, the latter using Levinson's trademark Camac connectors requiring either special interconnect cables or RCA-to-Camac adapters. These Camac connectors are superb devices, far superior to RCAs, but Levinson has been using them for over ten years without convincing anyone else in the industry to do likewise. Madrigal certainly believes in them, but I've always been bothered by the fact that their use requires the Levinson owner to replace all of the interconnects in his or her system, or else demands the purchase of RCA-to-Camac adapters for every connection point, thus making moot virtually all of the advantages of the Camacs, not to mention doubling the number of system contacts. The advent and growing popularity of XLR balanced connections may thankfully put a stop to the RCA-Camac confusion, at least at the preamp-to-power-amp interface.

Two pairs of five-way binding posts are furnished on the rear panel of the No.29, making bi-wiring a breeze. These posts are too far apart for double banana plugs for those who may still be fond of such connectors, but the open layout provides plenty of room for use of the more popular spade-lugs—with no cramped spaces and resultant concern for inadvertent short-circuits. You'd have to be a world-class klutz to accidentally short together any of the No.29's output terminals.

Technical details
The No.29 is a dual-mono design; it is essentially two separate amplifiers on a single chassis. Two 320VA toroidal power transformers are mounted on the inside of the front panel, well removed from the amplifier's low-level circuitry. The only disadvantage of this layout is that the amplifier is front-heavy; care must be taken when picking it up to allow for this significantly off-center weight balance. The entire bottom of the chassis is filled with very accessible, neatly laid-out circuit boards. There are three pair of Motorola output devices per channel; four flat, modestly sized aluminum plates both act as heatsinks and convey the heat to the chassis, with three output transistors attached to each.

The No.29's input voltage is capacitively filtered for RF before the power transformers. Surge protection at the transformer primaries minimizes turn-on stresses. At the output of each transformer's secondary and subsequent voltage rectification, power-supply filtration is provided by a pair of 15,000µF filter capacitors. Because these capacitors are smaller than those required in high-powered amplifiers, they can be mounted directly next to the output transistors on the audio circuit board, avoiding the need for buss bars to deliver the power supply's 33 available joules of stored energy. DC blocking capacitors are used at the 29's input and in its feedback loops. Levinson argues that with proper design this need not result in sonic compromise, and may help avoid a catastrophic malfunction from using a signal source with a high DC offset.

The No.29's low-level gain section consists of two bipolar, differential amplifiers biased into class-A. In the power output stage, local feedback is used both around each output device and around the entire output stage. A high damping factor at all audio frequencies is claimed. Proprietary circuitry protects the amplifier against overloads without, the makers say, degrading the sound. External and internal fuses (the former designed to blow first) provide additional protection, as do circuits designed to shut down the amplifier if DC appears on the outputs or if the heatsinks overheat. Soft-clip circuitry is also incorporated.

Sound
Focus, depth, and detail. The Levinson No.29 excels in all three of these vital characteristics. It makes a strongly positive overall impression, but it's hard to miss its strengths in those areas.

Focus—the quality that rivets images to their proper position in space, and which presents them in their proper size. Time and again I noted the Levinson's ability to pinpoint images and tighten the soundstage. Voices and instruments were sharply placed, not spread into some generalized "area." To a certain extent, this was loudspeaker-dependent; it was more apparent on the Apogee Stages than on the Mirage M-3s, which was not surprising since the former have, in themselves, a more focused sound. But it was not lost even over the more expansive, less immediate-sounding Mirages.

Depth—the No.29 presented the best sense of depth I've yet heard from the Stages. Ana Caram's Amazonia CD on Chesky (JD45) vividly demonstrated both the Levinson's depth and focusing ability, with a liberal helping of that third characteristic—detail—thrown in for good measure. One might argue with Ana Caram's intonation. Frankly, though I'm usually driven up the wall by off-pitch singers, it didn't bother me at all on this recording until Guy Lemcoe pointed it out to me—probably because I was concentrating more on the style. And on the sound, which is one of Chesky's usual fine efforts. With the No.29 driving the Stages, the lead-in percussion is sharp and vibrant. Inner detailing is sharp and crisp—in the best senses of those words. Individual "rattles" in the softly played maracas were clear.

At 1:14 into "Antonio's Song," the voice is doubled by a softly-played trumpet—which had not been obvious to me before. It wasn't that other amplifiers failed to reveal it, but that I became fully aware of what it was on its first play with the Levinson. The beginning of the title track is an excellent test for soundstage focus and depth, with very softly played, subtle detailing evident around, between, and behind the loudspeakers. The No.29 passed those details in a first-rate manner; they were convincingly and precisely focused laterally and sharply layered in depth, with a natural sense of air and space surrounding the whole.

The Levinson's low-frequency response lacked the drive and power of more powerful amplifiers, but within its power limitations, which are not at all as restrictive as you might think—like the Rowland Model 1, the 29 will put out well over 100Wpc into the low-impedance Stages—it is taut and well-defined. Taut, that is, within the context of the listening room and Apogee and Mirage loudspeakers, which tend to warmth. There's nothing about the LF response of the 29 which really grabs the listener without making direct comparisons to other amplifiers, except that it does not detract in any way from the openness and clarity of the rest of the amplifier's range. When compared with the far more powerful and expensive Threshold SA/12e, the Levinson does seem to have a slightly leaner, more transparent low end, but at some sacrifice in fullness and weight—especially the weight of orchestra or organ operating at full bore.

For all of its pristine clarity, detail, rendition of depth, and well-defined low end, the Levinson on occasion seemed to be somewhat laid-back, especially through the region of the lower midrange which lends body and fullness to instruments and voices. It lacked some of that "there" quality which provides for fully formed, three-dimensional performers. This was usually a subtle thing, most evident on voice. On Amazonia, Ana Caram's voice was somewhat cool and lean. The combined voices of the King's Singers on The Beatles Connection emphasized the separate voices at the expense of the resonance of the overall blend.

Despite that, when I compared the No.29 with the Threshold SA/12e over the Stages I found myself thrashing about trying to decide on a "winner." The amplifiers did not sound alike, but each had definite strengths in areas which did not always overlap. The Threshold was more "palpable" and immediate in sound, with a fuller, richer quality and a gutsier lowest octave. The Levinson was superior in the already mentioned areas of depth, detail, and focus. I have to say that the Levinson more than held its own in this comparison with a pair of monoblocks costing almost six times as much.

Further thoughts & Conclusions
First of all, it must be emphasized that I was more than somewhat surprised that I never really felt the need for more power with either the Levinson or the Rowland in driving either the Apogees or the Mirages. I wasn't blowing out the walls with the sound pressure, but I was definitely using levels which seriously compromise attempts at conversation. Nevertheless, it's impossible, from my vantage point, to determine if 50–60W (into 8 ohms) will be sufficient in your system under your listening conditions. Only a home trial will decide that.

With that important factoid on the record, it should be evident from my comments up to this point that while the Levinson No.29 and the Rowland Model 1 both made strong positive impressions, they also differed sonically. The Levinson excelled in those things which make a strong first impression, but never went overboard. Its sound was spacious and open, with a real sense of see-through transparency and a strong feeling of depth. Transients were alive: Michael Hedges's Taproot CD (Windham Hill WD-1093) had a vital drive and incisive attack which the Rowland insisted on softening. This sweetening was not unpleasant in this recording, which seems to have an inherent, electronic edge to it, but it did seem to lose a bit of its musical texture in the process. But on "I Carry Your Heart," the only sung track on the disc, the Rowland conveyed a vocal warmth and natural richness which the leaner sound of the Levinson slighted. And despite its tendency to soften hard transients, I found myself, with the Model 1, listening to bands on this disc which I had avoided before.

The slight softening of the Rowland was less in evidence on LPs than on CDs. But its delightfully musical timbre was evident on all good program material. It was never analytical or etched. Neither was the Levinson, though it was definitely more overt in its presentation of detail. The fingering details on Leo Kottke's My Father's Face LP (Private Music 2050-1-P) were more alive with the Levinson, yet the Rowland excelled in conveying the guitar's subtlety and warmth of tone.

When I tell you that the Levinson presented a more convincing sense of depth but that I felt the Rowland to be more three-dimensional, you may find yourself confused. [Yes—Ed.] Depth is front-to-back layering—distancing from the loudspeakers. Three-dimensionality is the sensation that individual instruments and voices have front-to-back depth within themselves and a natural, resonant timbre. Of the two, I consider the latter the more musically important.

The Model 1 also excelled in the reproduction of ambience. On "Lady Madonna" from The Beatles Connection, the cut opens with the King's Singers firing off a series of sharp, staccato notes. Over the Rowland, you can clearly hear the buildup of ambience as reverb from later notes builds on that remaining from the previous ones. With the No.29, though the ambience is still clearly evident, it seems somehow prematurely damped out, never quite building to the same level as it does with the Rowland.

As to how my sonic impressions of the two amplifiers varied with the loudspeaker in use, I had the most difficulty coming up with a hard preference with the Apogees Stages, perhaps reminiscent of Dick Olsher's difficulties in finding a totally happy match for those loudspeakers. But I found my glass 90% full with both amplifiers. The definition and focus of the Levinson was a powerful draw. The palpable quality of the Stages themselves compensated to some degree for a reduction in that quality in the Levinson, making for an overall performance which was detailed, well-defined in width and depth, and appealingly transparent. The Rowland, on the other hand, was a bit more relaxed, less obviously detailed, but with highs which could, with the right recording, be almost breathtakingly delicate and silky-smooth. The Rowland also had a midrange which was lucid, strikingly tactile, and musically convincing. Not an easy choice.

With the Mirage M-3s, I had a clearer preference for the Rowland. These speakers have more top-octave energy than the Apogees, making the crispness of the Levinson less appealing. Fortunately, the warmth of the M-3s somewhat balanced out the general coolness of the No.29. But with both loudspeakers, the more effective amplifier depends to a certain extent on the program material. If the latter demands a hard-driving intensity and hair-trigger HF transients, the Levinson excels. If it responds better to a more lyrical quality—to a warmth, fullness, flow, and three-dimensional rendition of instruments and voices—I'd have to come down on the side of the Rowland.

In the interest of fairness, I elected to listen briefly to both amplifiers using a different preamp. The Rowland Consonance was used for the bulk of the auditions for the simple reason that it is my current reference, but one might certainly argue that it could very well be synergistic with the Model 1. When Dick Olsher (with whom I currently share the Stereophile listening room, footnote 1) wasn't looking, I borrowed the Coda Technologies FET Preamplifier 01 he is currently auditioning and inserted it into my front-end. Everything else in the system was kept the same (at this point the M-3s were in use).

I had listened to the Coda very briefly during the final stages of my review of the Rowland Consonance preamp, and my general impression was that it was an excellent preamp with a somewhat "darker" sound than the Rowland. My general feelings of the relative merits of the two amplifiers didn't change, although with the Coda the Rowland edged a bit further into the "warmth" region, which suited even less material dependent on crisp transient leading edges for its full impact.

You might have figured out by now which way I lean. While I was delighted with the lively, deep soundstage conveyed by the Levinson, and even came to prefer it over the Threshold SA/12es for driving the Stages (with most program material), I was ultimately won over by the rich, fluid, naturally textured sound provided by the Rowland throughout the auditioning over both the Mirages and the Apogees.

But both of these amplifiers are compelling performers which belong solidly at the top of our Class B "Recommended Components" list. I pondered long on nominating them both for Class A status; neither misses that level by much, and on a given day I could be persuaded to promote them both to the top ranks. For a given listener, in the right system, either is capable of Class A sound.

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Footnote 1: Dick Olsher keeps his front-end on one side of the room, I keep mine on the other, and we rotate amplifiers and loudspeakers in and out of position as required.