Tube Power Amp Reviews

Notwithstanding unrectified current on all tube heaters, the Sevens never hummed—another testament to their excellent layout and construction. There were no unwanted noises of any sort, in fact, except for a soft and apparently harmless click that I heard when using the remote control to switch between triode and ultralinear modes (which, incidentally, is the handset's only function). The only problem I experienced was when the handset became taciturn, seemingly overnight, and would no longer work from distances of greater than a foot. I attempted a battery change, but became listless myself when I saw that the battery was an oddball disc type, and not the sort that I keep around the house.

Listening
An enthusiast of low-power amps, I didn't think I'd like the DiaLogue Seven's high-power ultralinear mode as much as its low-power triode mode. I imagined the former would sound smaller and fussier, more mechanical, and altogether more hi-fi than I prefer. I was wrong. Among other things, music through the PrimaLunas in ultralinear mode sounded every bit as large and present as through my Shindo Haut-Brion, itself a low-power amp in which pentode tubes are wired as triodes, but operated with a very small amount of global feedback.

In ultralinear mode the DiaLogue Seven was stunningly dramatic through both loudspeaker pairs. Georg Solti and Leontyne Price's recording of Verdi's Aida (LP, RCA Living Stereo LSC-6158) was intensely involving, from the great orchestral and choral tuttis of Act I, Scene 1 ("Guerra! Guerra! Guerra!") to those at the end of Act IV, Scene 1 ("Traditor! Traditor! Traditor!"). At the other end of the spectrum, the dynamic peaks within Jeremy Backhouse and the Vasari Singers' recording of Herbert Howells' motet Take him, earth, for cherishing (CD, United 88033) were consistently moving while never sounding harsh or mechanical. Lines of notes had very good momentum and flow, and vocal colors were fine.

In triode mode the DiaLogue Seven sounded softer overall, with a little less sparkle in its upper octaves—yet with more midrange texture, which can impart a sense of natural presence and detail even in the absence of an extended treble range. Similarly, in triode mode the DiaLogue Seven offered less bass content and impact than in ultralinear, as I especially noted when listening to César Franck's Grande piËce Symphonique, Op.17, performed by organist Torvald Torén (LP, Lyricon LRC 2-5)—which itself didn't have the floor-rattling capabilities of either the Haut-Brion or the ultralinear but feedback-free Shindo Corton-Charlemagne monoblocks.

My preconceptions were soon confounded in another way: I thought the DiaLogue Seven's comparatively soft, tubey triode mode would yield poorer temporal performance—musical timing, momentum, and the like—than its ultralinear mode. Again, that wasn't so. With the amps in their low-power mode, I very much enjoyed the final movement of Beethoven's Symphony 4 with Pierre Monteux and the London Symphony Orchestra (LP, Victrola/Classic VICS-1102)—a performance that lives or dies on the ability of one's gear to not muck up the timing. It sounded dazzling, as it should.

The same held true with pop music. As expected, the DiaLogue Sevens' triode mode helped tame overly crisp recordings, such as "Already Dead," from Beck's Sea Change (LP, Geffen B00004372-01). Low-frequency note attacks were also softened on that and other tracks from this album—but, again, I was surprised to hear little or no timing distortion on uptempo songs that depend on kick drum and electric bass for their sense of drive.

And though this falls afield of my usual performance notes, I can't resist mentioning the nearly unique clarity and directness—and the latter certainly is a quality I associate with low-power triode amplifiers—that the triode-mode DiaLogue Sevens brought to the Sprechgesang in Karl Bˆhm and Dietrich Fischer-Dieskau's famous recording of Berg's Wozzeck (LP, Deutsche Grammophon 2707 023). Many lines had me jumping in my seat, wondering why there were Germans in the house.

Which mode did I most enjoy? As much as the ultralinear mode earned my respect—and, in a number of ways, surprise—I ultimately preferred the DiaLogue Sevens' triode mode with both the Audio Note and Wilson speakers. Even on large-scale music, though the amps seemed more effortless in high-power mode, they compressed the peaks more gracefully in low-power mode, and consequently sounded slightly less mechanical overall. A fine example of that was on the song "Sabbath Morning at Sea," from Janet Baker and John Barbirolli's recording of Elgar's Sea Pictures (LP, EMI ASD 655): the London Symphony Orchestra's unmistakably Wagnerian crescendo was less sweaty in ultralinear, but somewhat more mechanical, too; smoothness, albeit with appropriate amounts of believable string texture, was greater in triode mode.

Where did the DiaLogue Sevens fall down? Nowhere, really. They committed no errors of addition, failing only to give even more of those things I love, available for a price from a few other sources: the more saturated timbral colors of a Shindo Corton-Charlemagne, the greater bass grip of a Naim NAP250, the even greater psychedelic presence of solo instruments and voices of a Fi 2A3 Stereo. Yet the PrimaLunas were more than satisfying in all those regards, and consistently impressed me with their flexibility and, perhaps more important, their value.

Conclusions
With each passing year, the products we buy seem more intimately tied to the circumstances of their creation. In a free society, it's okay to buy whatever we want. That said, it's also okay to be more selective than that, if you feel the need. For consumers as for everyone else, it's okay to care.

I'll bet PrimaLuna has that figured out, too, because it seems they've made peace with who they are: a company that could not offer such a combination of performance quality, build quality, and value without having some of their manufacturing done in China.

To some, those are dangerous ideas. To me, the most dangerous idea of all was right there on page 8 of the DiaLogue Seven owner's manual: "Have fun with [this amp] and never let people tell you what sounds right." I couldn't agree more.

From my experience, the DiaLogue Seven succeeds at everything PrimaLuna set out to do: It's an apparently reliable, obviously wonderful-sounding amp that offers higher-than-average value—and a lovely opportunity for you to discover the playback approach that suits your ideas about recorded music while, at the same time, having fun. Very strongly recommended.