I guess it shouldn't have come as a surprise, but I'd gotten so used to listening to superb solid-state amps and preamps from the likes of Soulution, BAlabo, and Technical Brain that I kinda forgot how terrific the ARC 610T tube monoblocks—now in combination with the great ARC Reference 5 preamp (which I will soon be reviewing in TAS), the ARC Reference Phono 2, the Walker Black Diamond Mk II, and the new Da Vinci Grand Reference Grandezza cartridge—sound.
It's simply amazing to hear how really good tube amps—and the 610T is the best I've auditioned—add space, dimensionality, and lifelike color, body, and texture to the soundfield. Take Sarah Vaughn (which I would gladly do, BTW) on her first Pablo LP "How Long Has This Been Going On?" If you know Sarah's soaring contralto, you know that she regularly added coloratura-like touches, including a throaty vibarto and a delicious head tone, to select lyrics. To hear her voice at its splendid best, you need to capture its power, its color, its range, and, for lack of better words, its volume—for all of her various coloratura touches come from slightly different places in the acoustic space that is "Sarah Vaughn on record" (and that was "Sarah Vaughn in life"). She variously uses her head, her nose, her mouth (actually various parts of her mouth, including a certain "chewiness" on select lyrics, as if she is actually tasting and savoring the words), her throat, and her chest to achieve that famous "operatic" range, timbre, and texture. In life, these things—head, nose, mouth, throat, chest—aren't a flat plane in acoustic space; they aren’t even a series of planes (which is the way they are generally presented on solid-state). They are one continuous “volume,” a single three-dimensional acoustic object .
With solid-state you generally (not always) get a pronounced flattening of this volume, just as you do to a greater extent with digital sources. HP once compared the effect to looking at the world through one eye, and I can't improve on that. With the 610T and the Ref 5, what seems more like "one-eyed" vision becomes binocular. It is quite an amazing difference to hear Sarah go from a relatively flat image to a fully round three-dimensional one standing in three-dimensional space and surrounded by three-dimensional space. It is also amazingly realistic. I've used the analogy before but it really is like the difference between looking at a large-format photograph and looking at a life-sized statue. The photograph, through two-dimensional, is very very finely detailed in a way that the statue isn't and it is also very realistic. But the statue is dimensional, solid, and lifelike in a way that the photo isn't.
Now there are some ilisteners who would claim that tube gear's "binocularity" is a distortion, a Doppler-like effect that leaves the impression of dimensionality where there really isn’t one. This may be. There is no question that solid-state has superior transient speed, better grip in the bass and treble, lower noise, and more precisely focused resolution of transient-related details. Indeed, I would be willing to concede that if you want to know what has been recorded on a record with the highest fidelity to the source, you are, more often than not, better off with solid-state. BUT if you belong to the "absolute sound" contingent (with one foot in the "sounds-good-to-me" camp), you simply have to hear the 1.7s driven by top-line ARC (or maybe, by extension, any first-rate tubes). It isn’t “the best” sound I’ve heard in my home, but it is one of the most astonishingly lifelike, everywhere but the lowest bass and maybe the topmost treble.