While the principle of “form following function” was originally associated with late 19th and early 20th century architecture and industrial design, Kevin Hayes’ and the Valve Amplification Company’s accomplishment with the Statement 450i iQ integrated amplifier under scrutiny here may be the most perfect example of that principle ever seen in the audio arts.
Towering to four feet in height, at just under ten-and-a-half inches wide and some eighteen-and-a-quarter inches in depth (sans the plinth it stands on), to my sensibilities it is as remarkable to look at as it is, as you will soon learn, to listen to. It is simply one of the most beautiful pieces of audio gear I have ever had the pleasure of laying eyes on.
The power transformers—the heaviest individual components and the devices most likely to deleteriously affect the signal—are in the amp’s base. The 450 iQ is dual mono throughout, so each channel of each section has an independent supply. While transformer-winding is fast becoming a lost art, the six main power supplies used here are bespoke VAC transformers, custom-wound in the U.S. All are stick-wound, EI core designs, affording superior rejection of the noise carried on the power line as well as high tolerance of DC line offset. And each one is also encapsulated in a special gel to damp magnetostrictive vibration.
Rectification is accomplished using a proprietary VAC technique, one that applies silicon rectifier elements in a manner that attempts to achieve superior current capability and low impedance regulation, while maintaining the smooth, low-noise behavior typically associated with vacuum tube rectification. This technique, aided by substantial energy storage ability, yields high inherent regulation. Both resistive and inductive filter elements are used in concert with high-speed capacitor assemblies for the high voltage supplies, while active voltage stabilization is included in the four preamplifier heater supplies. Finally, they are all sheltered behind a layer of EMI/RFI shielding.
Immediately above the supply section is the fully balanced amplifier stage. Fed from the dedicated dual-mono power supplies below it, it employs the same circuit topology and componentry as the $63,000 Statement 450S iQ stereo amplifier. The input and driver stages are Class A1, using direct-coupled low-mu triodes, Russian made Tung-Sol 6SN7GTBs. Its output stage uses eight Genalex Gold Lion KT88s in a rich Class AB1 ultra-linear (or “partial triode”) configuration, with a high voltage and high current operating point established by the VAC iQ’s Continuous Automatic Bias System. The output stage transformers are also custom wound in the U.S., using a very elaborate, heavily sectioned, bifilar design.
Next up is the linestage, essentially a clone of VAC’s $80,000 Statement Line Stage. Fully balanced, it utilizes medium-mu, Russian-made EH 6922s triodes in Class A1 operation, with transformer coupled input and output. [Class A1 is a more stringent application of conventional Class A operation.—RH] Hayes is quick to mention that this is essentially a small Class A1 balanced power amplifier with step-down transformer output—a circuit that also makes for an exceptional headphone amplifier. The transformer coupling and the lack of negative feedback effectively stops unwanted interactions between the power amplifier and the feedback loops in source components. The volume control is a massive, two-kilogram brass-cased and -shielded, four-section potentiometer that is expressly motorized for this application. While expensive (raw parts cost is over $1000 just for this assembly), motorization was the only way to realize remote control operation and afford the very best-sounding volume control.
Similarly, the phonostage sits at the zenith of the whole assembly, again using the same topology and virtually the same parts as the $80,000 Statement Phono Stage, omitting only one stage that is unnecessary in the integrated format where the interface to the next stage is already explicitly controlled. The circuit uses high-mu triodes, in this case, Chinese 12AX7As, in Class A1 operation and RIAA equalization is achieved passively, with no negative feedback. With dedicated step-up stages for low- and medium-output mc cartridges, and fully adjustable loading, the entire chassis is hand wired. While Hayes plays the rest of the details close to the vest, he did confide that he employs many “undisclosed” exotic components, like “naked” z-foil resistors.
This circuit description, though it accurately describes what I consider to be a truly inspired design, sheds no light on the beauty or functionality of this integrated amplifier. Mine was finished in a gorgeous three-tone paint scheme—black, silver, and red-bordering-on-burgundy. As noted in the description, the entire 400-pound tower is rectangular, save for a 2-inch-wide, 45-degree-beveled front left corner, all resting on a one-inch-tall, twenty-four-inch-deep, eighteen-and-a-half-inch-wide, bevel-edged black plinth, fitted with four one-inch-tall footers.
The left side is composed of a single panel, painted a dark gray, marked off into thirds by two horizontal grooves, with the centermost section bearing a large engraved VAC logo. While the grooves break up the visual monotony of one single panel, their main purpose is to help reduce and stagger the panels’ resonance modes.
The front is split into two sections, with roughly the bottom twenty-odd inch section containing the transformers/power supplies. It is finished in silver, with an elegant blue, back-lit VAC logo centered near its top that can be dimmed or turned off.