Tube Preamp Reviews

John Atkinson wrote about the Nagra PL-L in June 2008 (Vol.31 No.6):

Back in spring 1997, when Steven Lee of Canorus was visiting me in Santa Fe to help with the recording of Stereophile's Rhapsody CD (STPH010-2), he showed me some advance drawings of what would be the first high-end audio component from the venerable Swiss company Nagra, best-known for its jewel-like tape recorders (footnote 1). The PL-P was to be a full-function, battery-powered preamplifier built into a hardened, anodized, CNC-machined aluminum case with the same dimensions—12" wide (with jacks), 3" tall, and 10" deep—as the Nagra-IV tape recorder, and featuring the same multifunction Modulometer on its front panel. Unusually, I thought at the time, given my experience with the solid-state Nagra-D digital recorder, the PL-P was to be based on a circuit using eight tubes.

The Nagra PL-P made its public debut at the 1997 Stereophile Show, in San Francisco, and Jonathan Scull received a review sample that fall. As you can read in his report in the January 1998 issue, Jonathan plotzed over the PL-P. His verdict: "It's a fantastic-looking object, contemporary Eurochic, sleek and desirable." Though he did warn that it shouldn't be matched with lean-sounding ancillaries, he summed up that "It's the kind of preamp with which you can settle down for an extended tour....Class A down to its core."

The PL-P was followed by a line-stage version, the PL-L. This dispensed with not only the phono stage and its five tubes (footnote 2), but also the battery operation. (The PL-L is powered by an external 12V unit claimed to completely isolate the preamp from the AC supply.) Designed, like the PL-P, by Jean-Claude Schlup, the PL-L uses two ECC83/12AX7 dual-triode tubes and an ECC81/12AT7 dual-triode, each burned in for 12 hours before installation. Almost identical in appearance to the PL-P, the PL-L features four single-ended pairs of inputs (three on RCA jacks, one on XLR jacks with pin 3 tied to ground) and two pairs of single-ended outputs. A third output is available on XLRs; this is also single-ended, unless the optional, Nagra-made balanced output transformers ($600) are fitted. The price is $9495, including the remote-control, which used to be an optional extra.

Kalman Rubinson reviewed the PL-L in our November 2002 issue (see his review for a full description of the preamp's functions and features), and he liked it just as much as JS had loved its older sibling: "in terms of ambience and depth, [the PL-L] was the equal of the best units auditioned. The PL-L's quickness and microdynamics were noticeable....[The sound was] fast, balanced, and clean."

When I got the Nagra on my test bench, I, too, was impressed: "Overall, this is superb measured performance. While the PL-L should not be used into impedances much below 8k ohms...the gain structure and overload behavior are sensibly arranged with the expected audiophile usage in mind. Another Swiss jewel of a product from Nagra."

It was the realization, a year or so back, that this jewel was due to be eliminated from the magazine's biannual "Recommended Components" listing due to lack of recent experience that triggered this Follow-Up. Earlier review commitments kept pushing the auditioning back, but finally I set up the Nagra PL-L in my system (footnote 3). I used unbalanced cables from Linn to connect source components, but as the review sample was fitted with the balanced output option and I didn't have suitable lengths of unbalanced cables, I used balanced connections (Ayre's Cardas-sourced Signature Series) to the power amplifiers.

In his 2002 review, KR had noted that he felt the PL-L's direct-driven, single-ended outputs "were just a tad more dynamic and lively" than the balanced. But even using the balanced outputs, I found the Nagra to sound very dynamic. Very dynamic. As much as I love my Mark Levinson No.380S preamp, in direct comparison with the PL-L it sounded a bit fat and slow. Mark Flynn's "pay attention" snare-drum rim shots as he sets up the groove in "Blizzard Limbs," from Attention Screen's Live at Merkin Hall (CD, Stereophile STPH018-2), certainly made me pay attention—as did his three full-scale strokes on the snare drum later in the track: bap bap bap! I'd had to squash these peaks a little when mastering the CD from the original 24-bit files, but with the Nagra in the system, you'd never have known. The kick drum on this track didn't have quite the authority it had through the Parasound Halo JC 2, which I reviewed in March, but its low frequencies were still superbly well defined.

Throughout my auditioning of the PL-L, I kept jotting down words like clean and transparent; in fact, in this respect the Nagra resembled the Halo JC 2. With inferior electronics, you get the feeling that the spaces between the sounds of instruments become filled in, that everything starts to merge into everything else. With the Nagra, all remained discrete and nothing became blurred, even at high levels. Toward the end of "Blizzard Limbs," bassist Chris Jones hammers out a Bo Diddley beat, pianist Bob Reina plays arpeggios, and Mark Flynn taps out double time, first on his ride cymbal, then on his hi-hat, with a double backbeat on the snare. Meanwhile, under all this high-level musical energy, gonzo guitarist Don Fiorino is working on a small accompanying figure for which he uses a subtle chorus effect. This was neither obscured nor exaggerated with the Nagra in the system, it just was. As it was at the original concert.

The PL-L was also a master at the reproduction of recorded space, preserving the tiny clues that allow the listener's brain to reconstruct a simulacrum of the original space in which the recording was made. Its soundstaging didn't have quite the sense of magnificence that I'm used to with the Levinson preamp, which creates/re-creates a huge dome of ambience around the recorded event. Nevertheless, the space presented by the Nagra was coherent and stable, though with a more intimate feel than the Parasound and Levinson preamps. Hilary Hahn's solo violin in Vaughan Williams' The Lark Ascending, with Sir Colin Davis and the London Symphony (SACD, Deutsche Grammophon 28947-48732-6), for example, was more palpable, better focused than with the No.380S.

I had the PL-L in my system while working on the editing of the next Cantus CD, a collection of works by contemporary, predominantly American, composers, scheduled for release this summer. One piece, Eric Whitacre's Lux Aurumque, floats luminous tone clusters into space, where suspensions in the harmonies reinforce the reverberant hangover of the chords. Producer Erick Lichte had decided that we should place the mikes closer to the singers than in previous Cantus CDs, to get a more explicit image but without losing the supportive sense of space around the voices. The creative tension between Erick and me stems from the fact I look at the act of recording as capturing the image of a space that has singers in it, while Erick thinks of it more as recording singers who are within a space. The Nagra essentially preserved the balance between intimacy and ambience in Lux, though with a slight shift toward the former—favoring Erick's viewpoint, as it were. By contrast, the Halo JC 2 and Levinson No.380S favor my philosophy.

Other matters: I liked the fact that operation of the remote control causes a yellow LED to flash on the right of the preamp's front panel, to let you know it's seen you. Sheer good manners on the part of the PL-L, I feel. I also liked the relatively slow action of the volume up and down buttons—very unlike the speed-freak action of the Halo JC 2's remote volume adjustment. I loved the antique look of the front-panel Modulometer, though I must admit that I couldn't make out what it was telling me from across the listening room. My only quibble echoes that made by KR: rather than the more standard rear-panel placement, the PL-L's input jacks are on one side panel and its output jacks are on the other, making for awkward installations.

As Jonathan Scull said of Nagra's PL-P, you shouldn't pair the PL-L with lean-balanced amps and/or speakers. It proved a better match in my system with the Mark Levinson No.33H monoblocks than with the Parasound JC 1s, for example, and with the PSB Synchrony One speakers than with the Magico V3s or the Avalon Evolution NP2s. But with only that caveat, I strongly recommend the Nagra PL-L.—John Atkinson

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Footnote 1: Nagra–Kudelski Group S.A., Route de Geneve 22, 1033 Cheseaux, Switzerland. Tel: (21) 732-0101. Fax: (21) 732-0100. Web: www.nagra.com. US distributor: Nagra USA Inc., 357 Riverside Drive, Suite 230C, Franklin, TN 37064. Tel: (615) 726-5191. Fax: (615) 726-5189. Web: www.nagraaudio.com.

Footnote 2: Nagra offers a standalone phono stage, the VPS. Michael Fremer is working on a review.

Footnote 3: The new sample's serial number was 2552041. The original samples reviewed were numbers 5540331 and 5440346.