Balanced Audio Technology - REX 3 Röhrenendverstärker

The culmination of two-plus decades of research

The REX 3 all-triode power amplifier is the culmination of Balanced Audio Technology engineer Victor Khomenko's two-plus decades of research into creating the ultimate vacuum-tube power amp. A symmetrical single-ended bridge design featuring four of BAT's signature triode 6C33C tubes with zero global feedback and an extremely short signal path that maintains a linear response in both frequency and phase domains, REX 3 delivers 80 watts per channel in stereo mode or 160 watts in full triode mode when configured as a monoblock pair. Its custom-made output transformers are made to BAT's exact specification and have a wide-bandwidth frequency response from 5Hz up to 300kHz.

A truly different approach.

Think of REX 3 as two single-ended amplifiers per channel, with their waveforms summed at the output transformer. No direct current flows through the latter, allowing the output transformer to be a truly wide-bandwidth design all the while reducing low-frequency distortion. REX 3 extends the benefits of vacuum-tube current sources to include both the first and second gain stages of the circuit design. Hence, the linearity of the gain stage improves, the adjustments for the first and second gain stages become independent, and the tube current source components operate at a lower stress level.

Circuit improvements yield the greatest transparency ever heard in a BAT power amp

Just as BAT worked closely with Cardas Audio to improve its second-generation preamplifier and DAC output transformers, the company also selected an entirely new internal interconnect—constructed of the finest Cardas Audio Litz wiring— for the REX 3 power amplifier. Put simply, it is by far is the most expensive wire BAT has used in any component. Nothing was spared in the development of the REX 3 system. To complement Cardas Audio's wiring, BAT chose the finest copper-foil oil capacitors to replace its long-term oil caps. Sonically, the result combines BAT's hallmark naturalism with inimitable insight into musical textures, details, and expression.

New industrial design and logo

All REX 3 models replace the previous generation's steel fabricated parts with a new all-aluminum chassis and improved venting patterns to maximize ventilation and thermal dissipation for long life and reliability of all tubes and critical components. REX 3 debuts as the manufacturer's first tube amplifier available in an entirely silver-finished chassis. In addition, BAT's logo has been refreshed to clearly communicate its engineering philosophy: The symmetry of the three letters (with the "A" serving as a fulcrum) represents the company's famed balanced circuit design.

Plug-and-play simplicity in a no-compromise design

The all-triode REX 3 represents a technological tour de force of modern engineering applied to traditional vacuum-tube power-amplifier design. From the plug-and-play simplicity provided by its auto-biasing and electronic protection circuits, to the palpable illusion of recreating the original musical event in your home, REX 3 combines high-power output, beautiful midrange texture, and superb extension at the frequency extremes.

Intelligent auto bias and electronic protection

REX 3's advanced design eliminates the constant need to set and readjust the proper bias of the output tubes. An intelligent automatic-bias circuit adjusts for changing line voltage and aging tubes. For convenience, LED indicators show the status of each individual output tube. BAT further extends REX 3's plug-and-play nature with a novel fuse-less protection circuit that eliminates the power-supply rail fuses to provide both a more refined sonic performance and user-friendly experience.

80 watts per channel (stereo) or 160 watts per channel (mono)

The all-triode REX 3 offers a robust 80 watts per channel in the stereo version or 160 watts per channel when used in monoblock configuration. Its 6C33C-B triode output tube offers many times the current delivery of the more common 6550 tube employed in traditional push-pull designs. High-impedance vacuum tubes like 6550 require far more complicated output transformers than the low-impedance 6C33C-B type. Consequently, REX 3 remains quite comfortable driving low-impedance loads.