Balanced Audio Technology REX 3 Monoblock Power Amplifiers (pair)

A 160 Wpc symmetrical single-ended bridge design with 6C33C triodes

Balanced Audio Technology engineer Victor Khomenko has put two-plus decades of research into creating the ultimate vacuum-tube power amp. The REX 3 all-triode power amplifier is the culmination of this work; a symmetrical single-ended bridge design using 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.

This factory-configured monoblock pair offers 160 W per channel with each amp running in full triode mode. The custom-made output transformers are made to BAT’s exacting specifications, and have a wide-bandwidth frequency response from 5 Hz up to 300 kHz. The result is a presence and openness you can hear right from the opening note. 

An intelligent automatic-bias circuit adjusts for changing line voltage and aging tubes, with LEDs showing the status of each tube. An ingenious fuse-less protection circuit eliminates power-supply rail fuses for better sonics and ease of use.

Though a triode, the 6C33C-B output tube offers many times the current delivery of the 6550 tubes commonly employed in push-pull designs. Also, the high impedance of the 6550 tube requires far more complicated output transformers than the low-impedance 6C33C-B type. This allows BAT to spend money on sheer transformer tonnage and quality, and means the REX 3 is comfortable driving low-impedance loads.

Specifications

Output Per Channel (8 Ω/4 Ω): 160 W/160 W

Input Impedance: 108 kΩ

Gain (Nominal into 8 Ω): 26 dB

Tube Complement: 4 x 6H30, 6 x 6SN7, 2 x 6V6, 4 x 6C33C-B

Power Consumption (Idle/Full Power): 500 W/1,000 W

Dimensions: 17″ x 9″ x 24″

Weight: 100 lb