Mark Levinson ML-7A preamplifier Page 2
I had a brief listen to an ML-7A during a visit by Madrigal's Michael Wesley, and was able to determine only that (1) it sounded pretty bad initially, and (2) it sounded better by the end of our one-hour listening session. When my review sample arrived, I left the thing plugged in for 48 hours before giving my first listen. (I wonder, when I read lukewarm reviews elsewhere of solid-state devices with which I had been impressed, whether other reviewers adequeately allow for a proper warmup period.)
For several days prior to the ML-7As' installation in my system, I had been using a Kyocera CD-910 CD player connected directly into the power amps (a pair of the superb Threshold SA-1s) and thence to the MartinLogan Monolith speakers. This gave me a good opportunity to grow accustomed to hearing no preamp, in preparation for hearing the sound of the ML-7A.
So, what did it sound like? Well, it sounded much like no preamplifier at all, coming very close to the ideal "straight wire with gain." Because I was unimpressed with the quality of the high end on the first sample I heard, I paid first attention to the upper octaves when I fired up my review unit. Lo and behold, the ML-7A's high end was, quite simply, superb! Open, delicate, detailed, and completely texturelesslike live music. I have heard only one other solid-state preamp to equal the ML-7A's HF performance: the Klyne SK-5.
The ML-7A's high-level stages seemed to do nothing at all other than amplfication! Bypass tests, using an inverse-RIAA box, showed that the phono preamp stage was also doing its job and, as far as I could determine, nothing more. Initially, I had the impression that it may have been hyping the low-bass region, because marginal acoustic feedback (footnote 4) was more of a problem than I am accustomed to. But it turned out that the ML-7A's EQ is correct, and my C-J Premier Three is a bit weak at the extreme bottom. The ML-7A is, in fact, one of the most neutral, uncolored preamps I have ever tested.
It produced a soundstage of remarkable width, with very stable imaging which at times extended well beyond the lateral limits of the loudspeakers. This kind of thing sounds very impressive when it happens (from only a few stereo discs), but whether it is in fact desirable is moot; in a conventional stereo recording, nothing should image beyond the speakers. Extra-speaker imaging should only occur as a result of phase discrepancies greater than 90° relative to A+B, such as are introduced intentionally by SQ-encoded recordings and by devices like Carver's "Sonic Holography" generator, or inadvertently by poorly-miked stereo classical recordings. (Rock recordings can have large amounts of intentional phase discrepancies from the use of devices such as the Aphex Aural Exciter.)
The rendition of depth was also excellent, although there was less awareness of the stage boundaries, and less-distinct "layering" of the rows of instruments, than I hear from my reference C-J Premier Three. Inner detailing was superb, enabling one clearly to hear the individual instruments contributing to complex signals such as choral or orchestral tuttis.
The ML-7A was extremely quiet under most conditionsthat is, with cartridges having reasonable output. I did have trouble, though, with my reference cartridge, the Ortofon MC-2000, which does not have reasonable output: it's rated at a ridiculous 0.05 millivolts! Despite Madrigal's claim that the L-3 phono board is "designed for use with" the MC-2000, I got unacceptably high hum when I tried to use the cartridge directly into that board. Even with the preamp's phono inputs shorted, with so-called blind plugs (their "hot" strapped to ground), the hum measured a miserable 30dB below the cartridge's rated 1kHz output (3.75 cm/s modulation velocity). However, operation of the MC-2000 into the L-2 board's 50,000-ohm load, using Ortofon's own step-up transformer (the way I use this cartridge with other preamps), was satisfactorily quiet.
Although the overall sound of the ML-7A was very similar to what I remember hearing from the Klyne SK-5, I found the M-L to be a shade more agreeable; it had a little less of what I felt to be a subtle dryness in the Klyne. But the two are so similar in overall sound that I cannot choose one over the other for sheer accuracy. That would require a side-by-side comparisonsomething I will not be able to try until I get my hands on another SK-5. (Larry Archibald tells me a second sample of that unit is on its way to us.) For the same reason, I am not even going to try and decide which of the two I prefer. Actually, if I could choose either one for use with my present system, I would choose neither. The Premier Three's "euphonic colorations" make my loudspeakers (the MartinLogan Monoliths) sound better than no preamp at all, which is to say, better than does either the Klyne or the Mark Levinson. But if you are one of those twice-blessed souls whose system sounds best, in every regard, when you pipe your CD player or tuner or cassette deck directly into the power amplifier, then you need an SK-5 or an ML-7A.
How, then, would I rank the ML-7A in terms of value for the dollar? First, while I will freely admit that it is one of the two most nearly perfect preamplifiers I have had the pleasure of living with, there is no way I am going to pretend that I think its sound alone is worth almost $5000. In order for me to feel that way, it would have to sound much better, or much more accurate, than the Klyne. It doesn't, and I'm not sure it is possible for any preamp to, because the Klyne, too, is a virtual straight wire with gain. How then to justify the $2000+ price difference? Madrigal may argue that the ML-7A is better built and uses better parts, and they may in fact be right. But Klyne's products aren't exactly schlock, either, and I would hate to have to take a bet on whose products will outlast whose.
On the other hand, perhaps the two brands are not even comparable, because each seems aimed at a sufficiently different market that the question of competition may never arise. Comparatively speaking, Klyne Audio Arts has been in business a short time, and with a low profile; their products are known only to an exclusive inner circle of perfectionist hobbyiststhe people who read Stereophile and The Absolute Sound and Audio. Mark Levinson, through the years, has earned a reputation as the perfectionist's McIntosha brand that is most likely to be carried by salon-type establishments which specialize in selling systems to the carriage trade, rather than components to hobbyists. Unlike the audio hobbyist, such a buyer has little interest in staying abreast of the "state-of-the-art." He will buy the best because he can afford it, but as long as it continues to bring him listening satisfaction, he couldn't care less whether it is surpassed in a year or so by something marginally better. To him, it is more important that the system still be working properly three years hence, than whether its performance will still be state-of-the-art.
The audio perfectionist, however, is driven by a fury called State of The Art, which compels him to keep trading up every time the frontiers of design advance. Since obsolescence seems to happen in preamplifiers about once a year, no matter how good last year's preamps were, any premium he pays for five-year reliability is money down the drain. For the "serious" audio hobbyist, the fact that the Mark Levinson ML-7A may well be the most reliable preamp ever built is, paradoxically, the thing which makes it of questionable value to him. He probably won't own any preamp for long enough to derive much benefit from such durability.
Footnote 4: Borderline Acoustic feedback shows up as a tendency, at moderate to high listening levels, for the system to produce a prolonged "boom" rather than an abrupt "thud" when the base of the tonearm is gently tapped with the fingertip. Its effect on the sound is to emphasize bass and destroy its detail and control.J. Gordon Holt