Audio Research Corporation Reference 5 Linestage Preamp (TAS 205)

Meet the new boss in tube preamplifiers chez Valin.

No, it’s not the same as the same as the old boss of the Valin household, the Audio Research Reference 3, my reference tube linestage for the past five years. In fact, when I first plugged the Ref 5 in, it sounded so different than the Ref 3 I didn’t know what to make of it. Oh, it sounded good. It just didn’t sound like the Ref 3 or, really, like any previous ARC preamp (and I believe I’ve heard or owned most of them). It was altogether darker in balance, more tightly focused in imaging, denser in tone color, deeper-reaching in the bass and higher-reaching in the treble with much better resolution and transient response at both extremes than the Ref 3, but also relatively airless and bloomless for an ARC unit—closer to a solid-state sound than an ARC tube or tube-hybrid one.

I’d been forewarned that this sonic signature would change with time and break-in, and of course it did. But it took awhile—longer than I remember other ARC units taking—for the Reference 5 to come into its own. Several hundred hours of play, I’d reckon. It was worth the wait—kind of like staying up all night to watch the sunrise. In time, the darkness went away and in its place…light, air, bloom. Here was the ARC sound that I knew so well from the Reference 3 (and its long distinguished line of predecessors). It’s a sound you simply can’t mistake for that of any other brand of electronics, tube or solid-state—as clear, clean, and refreshing as a martini, and balanced, like a great martini, precisely on the edge between delicious and acerbic, without a trace of the saccharine Jack-and-Coke sweetness, darkness, and syrupiness that some folks seem to demand from their tube gear.

This classic ARC balance is, of course, a deliberate design choice and stems, as I’ve noted many times in the past, from the way William Zane Johnson has—from go—designed his tube circuits. It was his singularly great idea that tubes shouldn’t sound overtly “tubey,” that there was no reason they couldn’t compete with solid-state in the areas in which solid-state was superior (such as resolution, distortion, transient response, frequency extension) while retaining those things that tubes were better at reproducing (timbre, texture, bloom, air, dimensionality).

Just lately ARC has succeeded in this aim more fully than ever before. The Reference 5 is the best ARC linestage yet, higher in resolution, lower in tube-like coloration, better defined in imaging (though still life-sized) than the Reference 3 it replaces, with much better extension and grip in the bass and the treble. Although the technical changes between the Reference 3 and the Reference 5 (there is no Reference 4 because four is a bad luck number in the Far East, one of ARC’s major markets [and why the Vandersteen speaker between the Model 3 and Model 5 is called the Quattro. —RH]) may seem relatively minor on the surface, they are actually more significant than they look. While the tube complement of four 6H30s in the gain stage and a 6550 and 6H30 in the power supply remains the same as it was in the Ref 3, and the preamp is still (as always) a fully balanced, Class A triode circuit with zero feedback, capacitors have been improved and there are more of them with more power storage than in any previous Reference preamp. In addition, the main circuit board has been laid out horizontally rather than vertically in order to shorten signal paths (a first in ARC Reference preamps). The net effect, according to ARC, is a 3dB improvement in signal-to-noise ratio, which, of course, translates into an improvement in low-level resolution.

This is, indeed, the case. The Ref 5’s retrieval of low-level detail is consistently and notably higher than that of the Ref 3 (or any previous ARC linestage). For those of you keeping score, I would now rate it an 8.5 on a resolution scale of 10 (with something like the solid-state Technical Brain TBC Zero being a 10). For those of you not keeping score, it is not just the number of new things that you will hear through the Ref 5 that makes it special. (It never was with ARC gear.) It is the way these new things are combined with old things—the way timbres and textures are presented and instruments imaged and staged—that’ll make you gravitate toward ARC tubes (or not).

If I were to single out the two things that this ARC preamp supplies that great transistor circuits usually do not (at least to the same degree), it would be precisely the same things that analog front ends supply and digital front ends typically don’t: 1) three-dimensional body and bloom; and 2) very fine resolution of low-level harmonic/dynamic information, particularly on solo instruments or small ensembles. You might not be able to count the number of peaches in the crate with the same kind of exactitude that you can with a great transistor preamp—solid-state generally has higher resolution with large groups of things, tubes with smaller groups or individual ones—but when the recording engineer zooms in for a close-up of a particular peach you’ll perceive its roundedness, its dappled colors, its “fuzzy” texture with a realism that solid-state tends to scant.