Two New Tube Monoblocks from Octave Audio

by The Audio Beat | January 7, 2024

ctave Audio has added a pair of mono power amps to its extensive range of audio electronics. The new MRE 220 SE ($28,500 per pair) is the fourth generation of Octave founder Andreas Hofmann’s MRE amplifier series, which was first introduced in 1994. The MRE 220 SE uses four KT88 S4-A carbon-plate tubes (other tubes can also be accommodated) to output 220 watts, and it features an advanced pentode circuit that's at the core of nearly all Octave amplifier designs, due to its wide bandwidth, high resolution and stability into nearly any speaker load. A number of power-supply innovations ensure linearity and control down to the lowest frequencies. Among the numerous improvements over the previous generation the MRE 220 SE features a new output driver stage and the ability to adjust the damping factor. An optional Super Black Box power supply/capacitive-storage expansion module is available for use with the MRE 220 SE, at a cost of $7000 per pair.

Also new is the reference-grade Jubilee Mono Ultimate (shown right, $135,000 per pair), which uses eight KT170 tubes to output 440 watts. New proprietary circuit and transformer technologies are an important part of the amplifier's story, along with a newly designed driver stage, a new dedicated output-tube filament-heater power transformer, and a new output-transformer design that effectively increases secondary-winding surface area by 50% while reducing distortion-inducing skin effect. These developments and improvements bring an effective power bandwidth of 10Hz-100kHz, superior phase precision, and greatly increased dynamic range without an accompanying rise in distortion. According to Octave, "This all adds up to an extremely powerful-sounding amplifier with seemingly limitless extension and resolution at the frequency extremes, but with the natural and unfettered midrange one would expect from the most delicate tube electronics."

Both new mono amplifiers are handmade in Germany, with the most critical parts -- the power and audio transformers -- crafted in-house and specifically tailored to the needs of each amplifier. Both amplifiers feature an intelligent soft-start circuit, an electronic protection system, switchable damping factor, an eco mode for extended tube life, simple setting of bias, and a critically damped chassis.