VAC's "first principles" design approach led us to four critical factors in the design and voicing of the Statement 440: increased precision of
control over the drive/output circuit; control over stray interactions within the amplifier; architectural control of mechanical resonances;
and avoidance of electrically large, slow components.
The Very Low Impedance Driver (VLID) circuit gains much greater control
over the transfer function achieved in the output stage, improving
linearity and increasing headroom. There is palpably more control,
greater subjective power per watt, and increased detail.
Careful architecture and orientation of parts in 3D allows passive
control of radiated fields to an unprecedented degree for an audio
amplifier. Special consideration of they ways in which they interact
with the chassis, sensitive circuit points, and each other increases
purity and resolution. Modularization of circuit assemblies,
particularly the Modular Output Tube Assembly (MOTA), allows the
mechanical properties of the stages to be independently controlled and
optimized. Parasitic mechanical constraint of critical capacitors is
essentially eliminated.
While the MOTA techniques improve how the audio circuit deals with
mechanical energy input, the overall architecture of the amplifier
chassis and separate power supply minimizes the presentation of external
vibration. We start with 0.25 inch aircraft aluminum for a rigid basis, and
tailor the mounting points and couplings for the desired result. Between
the two chassis, 105 lbs. of custom magnetic transformers contribute to
the corresponding optimal mass loading. Custom machined feet provide a
slight, controlled decoupling of the power supply from the external
environment, while the audio chassis connects via a tripod of custom
designed stainless steel cups and balls, controlling of the flow of
vertical energy inputs and dissipating lateral energy inputs. The
proprietary VAC design provides a gentle yet powerful docking and,
unlike prior art, is not prone to dangerous instability.
With 440 watts RMS continuous output power (880 watts instantaneous peak
power) per monoblock give a great sense of freedom and ease, yet the
"first watt" is still pure. This is due in part to VAC's Very High Speed
Parallel (VHSP) technique, which uses fast, lithe devices in an analogue
parallel processing configuration that allows the speed and control
required to preserve delicacy and natural sound. Key elements include
specially designed output transformers with an astonishing 750 kHz
bandwidth, an excellent new implementation of the legendary KT88 beam
power tube, and an extended range of Class A1 operation.
In the external power supply there are three massive custom
transformers, which power seven separate basic supplies. These are
isolation mounted in a separate shielded segment of the power supply
chassis and potted in place with a special material to ensure low
mechanical noise and vibration. Proprietary techniques give the bridge
rectifiers the low noise associated with vacuum tube rectifiers, but
deliver the speed and high passive regulation inherent in silicon
diodes. Active voltage stabilization is used where appropriate. VHSP is
used in the filter banks, greatly extending the bandwidths of the
critical power sources. Six additional filter banks are located in the
audio chassis, directly at the points of use, for more than 400 joules
of energy reserve.
Balanced (Neutrik) and single-ended (Cardas rhodium) inputs are
provided, as are output connections (Cardas rhodium) to precisely match
loudspeaker loads of 2, 4, and 8 ohms. Bias monitoring it built it. The
finish is high gloss hand polished black or silver with 13mm glass.
The Statement 440 is entirely handcrafted by VAC in the United States of
America.
