Karlsbad, Germany | 2024 – After eleven years, and after extensive technical development projects at Octave, it was time to further adapt the MRE 220 mono power amplifiers – the rock in the surf – to the higher demands of modern loudspeakers. Long listening sessions led to the solution of an adjustable damping factor. The new MRE 220 SE damping factor can now be flexibly adjusted to ideally suit the respective speaker – resulting in rock solid reproduction quality with virtually any loudspeaker.
The MRE 120 received critical praise upon its introduction and for the 10 years it was in production. In 2004, it was replaced by the MRE 130 after a decade of experience and further development of the core MRE 120 design. The MRE 130 made improvements in detail retrieval and stability through refinements in its circuitry, most critically, in the output stage. Nearly another decade later, a major overhaul of the MRE series was undertaken based on the newly-developed KT 120 power tube. The KT 120 enabled greater power reserves and an even wider bandwidth in the MRE power amplifier output stage. Extended listening tests with a newly-developed output transformer and power supply led to the release of the MRE 220 in 2013. Its special virtues resulted in a unique combination of extremely high reliability with the utmost level of sonic finesse. The MRE 220 served as the optimal power amplifier for an unusually wide range of loudspeaker combinations. Whether employed in a bi-amp configuration with horn systems, or simply mated directly to a wide variety of high-end loudspeakers available in the global market, the MRE 220 remains a rock solid reference. Now, yet another 10 years later, Octave has taken the MRE series to another level: introducing the MRE 220 SE.
Today’s modern loudspeaker designs feature high-resolution and fidelity beyond what was achieved in the past. This, combined with the triumph of high-resolution digital formats and an extraordinary leap in vinyl playback fidelity, has led to an unprecedented quality of music playback in modern high-end systems. Despite all efforts, developing a power amplifier that harmonizes perfectly with all loudspeakers is – as experience shows – still very difficult, if nearly impossible. The requirements of the loudspeaker are too different in terms of power requirements, bandwidth and its performance, which is affected by the damping factor (and/or negative feedback) of the power amplifier.
In listening tests with many different loudspeakers during the MRE 220 SE design process, an important new tool emerged that ensures more optimal matching between our amplifier and a wider range of loudspeaker designs: an option to vary negative feedback that impacts the attenuation factor. Through use of chassis-mounted switches, the listener can choose between two damping factor settings, “LOW” or “HIGH”, along with separate settings for negative feedback. This is a completely new approach to the problem of a tube power amplifier that has to cope as well as possible with all the loudspeakers available on the market. With this unique adjustment option, the interaction of the MRE 220 SE with nearly any loudspeaker can be optimized almost perfectly. The result of this flexibility speaks for itself: an incredibly clear, spacious soundstage with a perfectly resolved and entrancing midrange that is free of any impurities, along with a silky, beautiful tonal balance.
Of course, the MRE 220 SE has power management with soft start electronics, the protection system and, like all power and integrated amplifiers, the Eco Mode, a BIAS setting and display, the power selector and a (Super) Black Box Connection. (See technology for description)
Super Black Box
The Super Black Box is a passive power supply extension designed for all Octave integrated and power amplifiers. Due to the massively increased storage capacity of the power supply, the pulse power of the power amplifiers is significantly increased. What is also very important is the increased independence from the electrical load – the loudspeaker. A big sonic benefit, not just for sophisticated speakers.
The Black Box is a smaller version of the Super Black Box with the same concept. It contains a circuit with electrolytic capacitors that increases the internal power supply of the amplifier and stabilizes it against mains fluctuations. Low-frequency network interference is perfectly suppressed. The black box has its own housing and is permanently connected to the amplifier using a special high-current connector.
|MRE 220 SE (pair)
|Silver or Black
|Per Amplifier: 4 x KT 88-S4A-Carbon, optional 4 x KT 120 TS or 4 x KT 150 TS
|Inputs: 1 x RCA, 1 x XLR; Output: Speaker output suitable for banana plugs and cable lugs
|488 x 229 x 412 mm (W x H x D)
|Adaptation to alternative power tubes
|Quiescent current display and setting
|Soft start; Protection circuit for amplifier and power tubes
|1 x RCA + 1 x XLR switchable
|Output power at 4 ohms
|High: 200 W (RMS) / Low: 140 W (RMS)
|20 Hz – 70 kHz / -3 dB at full power
|50 kOhm RCA / 25 kOhm XLR
|-116 dB (100 µV 150 Hz – 15 kHz)
|+29.5 dB RCA
|1 V RCA; 2 x 0.5 V XLR