VAC's Statement 452 iQ Musicbloc amplifier ($75,000 for a single amp; $150,000/pair mono, as reviewed) is tall, young, and lovely, but unlike the girl from Ipanema, it isn't tan. Nor, at 280lb in its flight case, is it likely to "go walkin'." Getting the pair moved into my listening room required considerable effortfortunately not mine.

Sized similarly to many modestly sized floorstanding loudspeakers, a pair of 452s makes for a striking physical presentation. They were first introduced to the public at the Capital Audiofest, November 2019though at AXPONA earlier last year, VAC demoed, in a large room, the Statement 450 iQ integrated amplifier, which shares the 452's stellar industrial design and, no doubt, much of its circuitry.

In my much smaller room, the look is even more dramatic and appealing. The thick aluminum chassis is finished in a clear metallic base coat, while other parts are copper, nickel, or chrome-platedincluding the stabilizing feet, which also call to mind the appointments of some floorstanding speakers.

The banks of horizontally situated tubes may at first seem unusual, but the arrangement has both formal and functional benefits. The layout is claimed to help air circulation efficiency, since warm air rises, resulting in better tube cooling and a narrow footprint: approximately 9" wide and 21" deep (and about 2½' tall), which makes this big amp more small-roomfriendly. In addition, according to VAC, the vertical alignment helps keep signal runs short, allows for a ground reference that's very tightly shared between stages, places the power supply as close as possible to the circuitry that needs high current, and locates the sensitive circuits as far as possible from potential sources of noise. And gravity, it's claimed, helps damp the tubes.

A powerful and versatile tube amp

The 452 is a fully balanced, direct-coupled (no coupling caps between input and driver tubes), class-A input, point-to-point hand-wired design that uses four Tung-Sol 6SN7 twin-triode tubes (new tubes, not new old stock) for voltage amplification and as drivers. The output features eight Gold Lion KT88 beam power tubes operating in Ultralinear. The design is fully compatible with KT90, KT99a, KT120, and KT150 output tubes. Each 452 amp employs a total of eight VAC-designed transformers in aggregate, weighing a total of 120lb.

VAC specifies the amp as outputting 225Wpc in two-channel mode or 450W in single-channel mode (see below), both into 4 ohms, though this varies somewhat depending upon powerline "stiffness" and output tube condition. Output into 6 or 8 ohms isn't specified. Frequency range is spec'd at 4Hz75kHz, with power bandwidth listed as between 20Hz and 70kHz. If the amp meets or comes close to meeting those specs, there's power aplenty for all but the most insensitive loudspeakers. The published specifications are minimal; I wish more information was provided.

According to VAC, the output design achieves class-AB operation using its patented iQ Intelligent Continuous Automatic Bias System, which the company claims is "the only known approach to allow the true underlying quiescent current (bias point) of the output tubes to be monitored" and held steady at all times, resulting in more stable tube operation and thus a more stable loudspeaker interface. In other words, the system monitors and adjusts the bias current in real time, compensating as the amp warms up, as the power line varies, as tubes drift, and when you change the volume. The system is claimed to also prolong tube life.

Premium parts are used throughout, including metal film and wirewound resistors, custom film and foil caps, and Cardas rhodium connectors.

The versatile design allows the 452 to be used as a dual-mono stereo amplifier or, at the flip of a pair of rear panel-mounted switches, as a single-channel amp; VAC loaned me a pair of 452s, which I used only as monoblocks. There are three sets of binding posts: a single set for mono operation and a pair for stereo. The amp can accept single-ended RCA inputs, but those are converted via a transformer to balanced operation, which is not the ideal way to create a balanced inputso it's best to use a fully balanced preamplifier. The front panel's blue LED-lit VAC logo can be either brightly or dimly lit or turned off, which is a nice feature.

Setup and use

Flip the on/off switch and, in a minute or so, the amp is ready to gobut I found that it takes about a half-hour's warm-up time to sound right. Upon turn-on, the sound is somewhat thick and veiled, with soft transients. Designer Kevin Hayes suggested turning the amps on in the morning and off at the end of the final day's listening session, which is what I did. Many of those sessions ended stupidly late at nightactually early the next morning.

The iQ system includes a front-panel LED monitoring system, one LED per output tube. If an LED glows green, it means the associated tube is weakening and should be replaced when possible. Meanwhile, the circuit will automatically compensate by upping the bias. If an LED glows red, the associated tube is drawing excess current, causing a possible "runaway" condition, usually produced when a component within the tube fails. In that case, the system will shut down the main power supply before a fuse can even blow, preventing amplifier damage.

Hayes left a box of extra tubes "in case," but none were needed during the two-monthlong review period, nor did an LED glow green. The amps ran trouble-free and so cool that it was like not having a tube amplifier in the house at all. If I were designing a big tube amp to be used in VAC's Florida home, I'd aim for that.

Smooth but not too smooth?

In case you're wondering where my "The Girl From Ipanema" reference came from: When I wrote that opening paragraph, I was listening to an original pressing of Stan Getz and João Gilberto's Getz/Gilberto (Verve V6-8545), engineered by the late, great Phil Ramone in March 1963. So, why not start the sonic description using that familiar record, which has been reissued on vinyl by Mobile Fidelity, Speakers Corner, Analogue Productions, UMe (an awful-sounding version on orange vinyl cut at GZ Media from a digital file), and, soon, by Impexis this last one sourced from tape? We'll see.

If any record can be ruined by an overly warm and soft-sounding tube amp, it would be this one, which already has so much built-in warmth in the upper bass/lower midrange. On "The Girl From Ipanema," percussionist Milton Banana's jingly accompaniment is distantly miked and placed purposely down in the mixit's barely audiblewhile João Gilberto's bossa nova rhythm guitar plucks hover gently in the air just below his warm, chesty vocals. Pianist (and composer) Antônio Carlos Jobim, barely striking the keys, taps out occasional piano fills, and an uncredited bass playerit's Sebastião Netoadds an equally gentle, minimal foundation. Only Getz's feathery, wet sax pushes well forward in the mixand of course Astrud Gilberto's almost whispered voice floats subtly out of one channel (right on the original, left on the reissues; mastering engineer Kevin Gray insists that the original had the channels reversed).

The VAC amp nailed this track, as if it were voiced specifically for it. Especially noteworthy was how the 452s reproduced the subtle jangle of Banana's percussive accents: metallic, not "velvet," and in a discernible space well back in space, the envelope of which was visible (sonically) in the backdrop. Neto's bass lines were supple, yet the attack was sufficiently forceful and well-defined to rhythmically drive the tune. Gilberto's plucked-chord rhythm guitar fills were fast and cleanly delivered in a well-delineated three-dimensional space. Getz's breathy sax sat centerstage, well in front of the rest in three-dimensional relief. The whole was vivid, relaxed, well-defined, and as wide open and naturally delivered as I've ever heard the trackand I bought the original pressing in 1964 when it was first released.

By the time I wrote my opening paragraph, I'd spent almost two months of solid musical enjoyment, marveling at the relaxed and fully immersive presentation. No wonder Herb Reichert described the sound produced by two pairs of these amps, biamping a pair of Von Schweikert Ultra 11 speakers, as "Bigger than any Wilson WAMM or giant Western Electric theater system I have experienced. The soundstage went from heaven above and around the globe."

Herb needs to hear the WAMMs driven by the Statement 452 iQs to be sure of that, because the soundstage produced by a pair of these amps on the Alexx in my room was wider, taller, and especially deeper than anything I've ever experienced here (other than through the enormous Sonus Faber Aida loudspeakers, which have a rear-firing multidriver array).

As expected, individual images, too, were larger than the somewhat more compact ones produced by my reference amp, but both were soundstage proportional. (Which is not to say my amps produce too small a picture, or the VAC amps too large!)

Sometimes I felt these amps produced a picture that was too large for my room, which of course is a room issue, not an amp issueif it is an issue at all. Other times, the volume of space produced was simply breathtaking and transportive, as on the recent AudioNautes Recordings reissue of O Magnum Mysterium (AN-1801), originally released on LP in 1993 by Chesky Records (CR83) and cut by Paul Stubblebine.