Mono Amplifier 2 X 150 watt/4 ohm

The MRE 130 mono amplifiers are push-pull power amps in pentode configuration, producing approximately 140W per channel at 2% THD. The MRE 130 monos are designed to reproduce the vast scale of a large orchestra in its entirety. From the deepest bass, to the highest note- all the musical information is conveyed without loss of dynamic details. Raw emotion, stunning detail and rich voices - the MRE delivers fireworks. There are power amps on the market which can’t run because of the power they have, whereas the MRE 130 can sprint. The sum of all its sonic characteristics makes the MRE 130 a suitable partner even for the exalted Jubilee preamp.

OCTAVE power amplifiers have always set new standards. With the introduction of the original RE 280 stereo power amplifier, Andreas Hofmann left traditional power amp technologies far behind. With the MRE 130, Hofmann has gone one step further. While it has the same power management and optimized input stage as its stereo brother, the MRE 130 benefits from an innovative and enhanced output stage configuration. What is revolutionary about this new generation of amplifiers is that OCTAVE has employed the classic, yet almost forgotten, pentode configuration.

The classic pentode configuration was quite commonly used in earlier power amplifiers. It offered the benefits of reliability and a relatively high power output. From a modern perspective, its disadvantage was reduced dynamic stability and a high level of distortion. These effects are not a direct result of the pentode itself, but rather of the circuitry employed at the time. Andreas Hofmann has now developed a new circuit design that eliminates the drawbacks of the classic pentode configuration. This novel design involves the use of a second, separate power supply circuit for the auxiliary current required for the pentode mode of operation. The characteristics of this enhanced pentode circuit employed in the MRE 130 are virtually ideal from both a sound quality and an engineering point of view.

Black Box Connector

OCTAVE, with the Black Box technology, offers an upgrade path for optimizing the OCTAVE amplifier in respect to the speaker. This flexibility is a unique feature of the OCTAVE brand.

The dynamic and tonal stability of an amplifier is strongly dependent upon the stability and capacity of the power supply, therefore the Black Box and Super Black Box were developed as external upgrades to the OCTAVE amplifiers’ power supply storage capacitors by increasing their capacitance by a factor of 4 (Black Box) or 10 (Super Black Box), respectively. This is a tremendous benefit if the speaker is difficult to drive. Loudspeaker efficiency is made less critical, while the amplifier is enabled to handle speakers with extremely low minimum impedances.

BIAS Adjustment

The Output stage of the MRE 130 operates in Class A/B, and therefore requires an adjustable BIAS regulation. The highly sophisticated yet extremely simple yet accurate BIAS calibration system is accessed on the front panel of the unit. It utilizes external precision bias trim pots and LED confirmation, allowing the user to readily monitor the output tubes and simply correct their bias individually at the top panel - without the need of a micrometer let alone any special knowledge or tools.

The correct BIAS is vital for the constant sound quality of the MRE 130. Due to this facility there is no need for a technician to service the MRE 130 for changing or tubes or to check their condition. The precision of this user friendly system is within 0.5% accuracy.

Power Management and Protection System

The MRE 130 is equipped with a multi-stage Soft-Start/Turn-On protection circuit which extends component as well as tube life considerably by protecting against stress caused by typical high inrush currents during switch-on. The unit starts in a defined sequence, with the Protection System monitoring the MRE 130 completely, and activated whenever a malfunction is detected. Once the Protection is activated, the MRE 130 is powered down.

Total Harmonic Distortion:

Curve 1: BIAS adjusted correctly | Curve 2: BIAS 10% out | Curve 3: BIAS 30% out

Frequency Response:

Between 10Hz and 90kHz the frequency response tolerance is just 0.3dB.

Interfering Signal Spectrum at 3 V / 1 kHz Output Level:

The FFT-Analyse recorded an extrem spectral purity from Output signals. Disturbances from mains (normaly 50 and 100 Hz) are missing

Harmonic Distortion between 30 Hz and 20 kHz: