Balanced Audio Technology

While this company is best known for its vacuum tube gear, it also manufactures some of the best solid-state equipment we've ever heard. The latest such offerings are the VK-85 preamplifier ($12,500), the REX 300 power amplifier ($15,000), and the REX 500 power amplifier ($25,000).

Introduced simultaneously with the REX 300 power amplifier, the Balanced Audio Technology VK-85 preamplifier blurs the lines between the finest tube and solid-state sound. The VK-85 features BAT's trademark high-current, Uni-stage topology with transformer-coupled outputs that anchor the full line of Balanced Audio Technology's preamplifiers. the VK-85's second-generation output transformers work in conjunction with a symmetrical N-Channel, Uni-stage gain block to provide the high-current operation that is a BAT hallmark. A revised connection scheme for the SuperPak Quattro technology used in the REX 300 offers beguiling levels of musical finesse and textural beauty.

The revised power supply of the VK-85 incorporates the same fourth-generation, SuperPak used in the REX 300. In addition to providing four levels of filtration, it is connected in a new manner that dramatically lowers the preamplifier's overall noise floor. The parts used in the SuperPak Quattro include premium silver foil/oil capacitors that improve harmonic accuracy and go far beyond the types of capacitors found in most power supply bypass designs.

Simplicity of design, especially in the direct signal path, remains a hallmark of Balanced Audio Technology's purist approach to circuit topology. The signal in the VK-85 is transmitted through only one gain stage, one free from the negative artifacts attributable to both extremes of modern preamplifier designs: passive preamplifiers and multi-stage buffered, active circuits. BAT's trademarked Uni-stage circuit provides the ultimate simplicity by amplifying the incoming signal just once while using no global feedback to deteriorate the integrity of that signal.

The VK-85 circuit is based on N-Channel MOSFET devices. Solid-state designs customarily use complementary N- and P-Channel devices in the gain stage. Such configurations are easier to build but suffer from an important drawback: P-Channel devices are inherently inferior to their brethren, N-Channel devices, because they are much slower. In the VK-85, both halves of the musical waveform are handled by identical devices, in identical circuit configurations, assuring symmetry of the resulting music signal.

The gain stages of the REX 300 feature ultra-high current delivery to achieve spectacular transparency and dynamic realism The amp also employs the same split power supply topology (Twin Path) as REX 500. These individual power paths allow the supply to deliver much greater current than traditional designs. The power supply design is further enhanced by BAT's SuperPak Quattro capacitor bank, which provides four levels of power-supply filtration. In the SuperPak Quattro, third-generation premium silver foil/oil capacitors are joined by an X-cap further to flesh out music's textural beauty and tonal density.

The REX 300 incorporates the same protection circuit used in the REX 500 to eliminate any need to use or replace internal fuses. Many of us have experienced power surges at home and the resultant blown fuses. If you experience a shutdown for any reason, just press the rear-panel reset button to restore normal operation. That's it! The elimination of internal fuses also permits the REX 300 to handle higher currents without impeding the circuit's operation. As always, the best-sounding fuse is no fuse at all.

The REX 300 amplifier circuit consists of just two gain blocks. The theoretical ideal for any power amplifier would be to have only one gain block. But the single-stage amplifier is only possible with low power output. Thus, the REX 300 stands at the zenith of simplicity for modern high-power amplifier design. The REX 300 uses only N-Channel devices for the same reasons as outlined above for the VK-85. True to BAT's name, the REX 300 is also fully balanced from input to output.

The REX 300 can be ordered as either a stereo amplifier or as a mono-block. BAT also provides a simple upgrade path that allows the owner of a stereo REX 300 to convert easily to a mono-block setup. You don't need to trade your amplifier in to obtain more power. Simply convert your existing REX 300 to a mono-block and order a second REX 300 mono-block to match. Technically, the stereo to mono-block conversion is accomplished by paralleling the inputs and outputs. This means the performance gets even better since the current delivery doubles and becomes more effortless, like the sound of live music.

Balanced Audio Technology's flagship solid-state power amplifier, the REX 500, represents the culmination of the company's decades-long pursuit of sonic and engineering excellence. Victor Khomenko, BAT's chief designer, observes that “BAT has never designed for power alone, and I am most proud of the elegant simplicity in how the REX 500 delivers that power." For those who demand numbers, the stereo version produces 500 Watts/channel into eight ohms and 1000 Watts/channel into four ohms. In the mono configuration, let's just say that the power is more than adequate.

Being a true dual-mono design with independent channel assemblies, power transformers, and separate power cables for the left and right channels, the REX 500's design is a purist approach that offers benefits in the areas of soundstaging, depth, dynamics, and insight. The gain stages of the REX 500 feature the highest current delivery ever achieved in a Balanced Audio Technology design. The REX 500 also employs a new power supply topology (Push SuperPak) and the largest SuperPak (as measured by energy storage) of any product in BAT history. From its extraordinary 500 Watts/channel of power delivery to the peace of mind provided by the elimination of fuses, the REX 500 stands as the pinnacle of BAT solid-state design. Add to that the simplicity of a circuit that features only two gain blocks, zero feedback, and the pure symmetry afforded by using only superior N-Channel devices for amplification, one can understand why this statement product is unique. And if you REALLY feel that you need more power, you can always convert your REX 500 to a mono-block and purchase a second one!