audio research
VT50

The least expensive of the latest- generation "VT" series of vacuum-tube power amplifiers from Audio Research, the VT50 is compact in its physical dimensions, but has sufficient output (with hefty distributed power supplies) at 50 watts per channel to effectively drive and control just about any moderately efficient loudspeaker available today. It suffers not by sonic comparison or in musical resolution, but only in loudness cabability in a given music system. Even so, comfortably realistic levels with surprising musical dynamics are easily within the VT50's grasp.
Based on the same circuit design as the VT100 and VT200, the VT50 features a dual-mono circuit layout reaching back to the large power transformer. Two matched pair of 6550-C tubes provide the output (one pair each channel), while four 6922 twin triodes serve as input and driver tubes (two each channel). Constant-current source technology (as used in the Reference Series) help maintain output stage balance and headroom under dynamic music conditions. Distributed power supplies yield a total energy storage of 354 joules (compared to 183 joules in the CA50), giving the VT50 remarkable dynamic snap in addition to its inherent sweetness and delicacy. And, like its more powerful siblings, the VT50 provides the convenience of both balanced and single-ended inputs for easy connection to any quality preamplifer.

Chassis design and size are identical to the CA50/REF1 mechanical package, but of course without front-panel control knobs. A simple oversized rocker switch provides power on/off. Output terminals offering 4-8-16 ohm impedance options are of the heavy gold-plated type used on larger Audio Research amplifiers. Power cord is a detachable 14 gauge with IEC connector.

For moderate or high-efficiency high- resolution loudspeaker systems, the VT50 is a natural mate. Paired with dynamics or electrostatics, the VT50 makes music come alive, with surprising dynamics when called for, vivid midrange transparency and image focus, and delightfully non-fatiguing upper-frequency extension and air. This is a power amplifier sure to become a favorite of music lovers who appreciate accuracy and nuance without the bombast.