Solid State Preamp Reviews

The second, more common category is that of components which appear neutral but actually have subtle problems which detract from the enjoyment of the music, resulting in cold, rather clinical sounds. Examples which spring to mind are the original PS Audio IV, the West German Burmester, the Klyne SK-5A, the Krell PAM-3, the original British Fidelity MVT, the Meitner, the now-obsolete Meridian 101, Quad's 44, and the Audio Research SP9 (footnote 6). These models are termed "accurate" by many listeners (and their designers, of course), who point out that if the music isn't enjoyable, it is because the "accuracy" allows the faults in the recording to be clearly heard—it is not the preamplifier's fault that the truth is unpleasant. I feel, however, that unless you have a masochistic streak, the negative effects on music cannot be overlooked. In my opinion, a truly accurate preamplifier will make all varieties of music more listenable, even music that wasn't well recorded in the first place.

Until the Mark Levinson No.26 came along, the only preamplifier of all the ones I had used which I felt to be both accurate and musical was the Krell KRS2. (Although listening to Threshold's FET/10 in Gordon's system leads me to believe that it, too, might be a contender.) Now there is another! While sounding different from the Krell, the similarly priced No.26, too, appears to impose no significant sonic signature on the music.

Read that last sentence again. Yes, it's self-contradictory. If both preamplifiers are neutral, then they should sound the same, right?

The fact is that, to judge by my previous standards of preamp performance, both are neutral. Insert either one into one of the tape loops of the other; flicking the tape-monitor switch reveals there to be no change in the sound. Over a longer period of use, however, as my range of experience broadened above what I previously found to be the limit of neutrality, I found that they are slightly different, the Krell having a more forward presentation, a more "robust" sound. By comparison, the No.26 offers a slightly more transparent, more detailed midrange with, overall, a more delicate quality. Both have extended, tight bass performance and a treble refreshingly free from grain. Both have soundstaging that borders on the breathtaking, with the ability to throw a deep, well-focused image. (Those who say that this is purely a result of the "false ambience" tubes possess should make the effort to hear either of these solid-state preamps.) More importantly, both let the music through unscathed by the perils of its passage. Either could be the "best" preamplifier in a particular system.

I suspect that what I in fact hear from these two preamplifiers is the slight imposition of the designers' own personalities on their products. Though neutrality is always the final goal, when it comes to the fine print of that neutrality—the choice of components and wiring, the layout of the pcb traces, what in a loudspeaker is termed the final "voicing"—the designer's own taste will inevitably imprint itself on the final sound.

When it comes to the No.26, its sound—or lack of it—seems to impose nothing negative on the sounds of instruments and voices, the reproduced soundstage, or the music. It is a reference-standard, truly transparent preamplifier.

A power amplifier could be said to have a harder job than a preamplifier. Whereas the latter operates under electrical conditions which remain pretty constant, an amplifier has to be able to track its input voltage with its output to a very close tolerance while delivering arbitrary and often extreme peak currents into the loudspeaker. In addition, it has to be able to sink back-EMFs from the loudspeaker motor system, reaction voltages produced after the event, without these having any influence on the signal. The No.20 could be thought massively over-engineered by conventional standards, yet in practice, faced with real-life loudspeaker loads and on all kinds of music, it never failed to deliver the musical goods.

Conventionally, a reviewer is expected to dissect a component's performance, band by area by band, pointing out deficiencies here, positive aspects there. With components like the No.20 and No.26, this is hard to do: it is the whole performance that impresses—as it is with the real thing. But if there is one aspect that should be picked from the whole with the No.20, it is the low end. Even with the SL600s, low frequencies took on a weight, an authority, that totally belied the measured extension. This has always been a characteristic of the Krell amplifiers; the No.20 goes even farther in this direction. The New York Times tells me that a Led Zeppelin revival is under way. Would you believe that the No.20s made "Whole Lotta Love" sound like heavy metal was the natural diet for the SL600s! With amplification of this caliber, small speakers can deliver what my friend Ricardo Franassovici terms "The Big Sound." (He thinks that I am too liable to be seduced by this—but then, he is a Krell and Audio Research distributor.)

This is not at the expense of smeared-over detail. Listening to the late-'50s Bruno Walter Mahler 2 recording on CBS, I was made very aware of the artificial nature of the recording—the solo violin echo of the contralto's "Hast nicht umsonst gelebt, gelitten!" is both in a different acoustic from both orchestra and singers and has a different quality of tape hiss—but was still swept away by the music. And when the organ pedals underpin the timps' and basses' falling-fifth motif at the work's conclusion, even small speakers driven by No.20s destroy you with the sheer weight of the sound.

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Footnote 6: You will notice that missing from either list of preamplifiers, all of which have spent time in my system, is Audio Research's SP11. Not having used one in my home, I am wary of mentioning it. Based on my experience of it in other systems, however, I am ambivalent concerning its ultimate performance. The sound of the Mk.I didn't persuade me to replace my SP10; the Mk.II I have yet to hear.—John Atkinson