OCTAVE Audio

Black Box

The Black-Box is an external Power Supply Booster.

Super Black Box

The Super Black-Box is an external Power Supply Booster with enhanced Capacity.

RE 290

MRE 130

MRE 220

RE 280 MKII, the Elegant

The RE 280 MKII stereo amplifier is a push-pull Class A/B power amplifier in ultralinear configuration, rated at approximately 2 x 70W peak power output at 2% THD. The sound of the RE 280 MKII is wide, open, with natural timbre. Listeners don’t think that they are hearing an amplifier, as everything fits and flows harmonically. The RE 280 set new standards in the year of its initial launch.

This was in 1994; the current RE 280 MKII variant is now in the third technological generation of this model. The most important improvements realized were in the manner the amplifier delivers power. Performing without strain, the RE 280 MKII is always in control of the situation. Many manufacturers neglect to include electronic protection systems in their tube amps, which means that the life - and indeed the operational safety - of these amplifiers is greatly dependent on factors over which the user has no control, such as the failure of a tube or a short-circuit of the speaker.

OCTAVE equips its power amplifiers with an electronic protection system as a matter of course. The technical breakthroughs that set the original RE 280 apart were its optimized input gain section and power supply. Indeed, it used a totally new power supply design, featuring double grounding and supply voltage isolation. The optimization of the input stage provided absolute immunity from influences such as the loudspeaker reactive load, together with excellent phase stability for highly accurate push-pull operation and an extension of the usable frequency range from 10 Hz up to 80 kHz. From a sound quality point of view, these enhancements delivered a consistent tonal performance that remains independent of the impedance response and efficiency of the speakers.

Basic Model		Stereo Power Amplifier with 2 x 70 Watt
Tube Complement		4 x 6550, Driverstage Tubes: 3 x ECC 82
Design		Aluminium silver or Aluminium black
Add On Modules		Black-Box and Super Black Box

Specifications

Power Output

2 x 70 Watt into 4 Ohm

Frequency Response

10 Hz - 80 kHz / ± 0,5 dB

Total Harmonic Distortion

< 0,1% at 10 Watt into 4 Ohm

Signal-to-Noise Ratio

> 100 dB

Minimum Speaker Impedance

2 Ohm

Gain / Input Sensitivity

+ 30 dB / 1 V

Download:

Owner's Manual


	General Facts

	Power Consumption		160 Watt idle, 320 Watt at full power

	Standard Accessory:		Power cord, 3 mm Screwdriverr for BIAS Adjustment, 1 sparetube KT88/6550

	Weight		24,5 kg each Amplifier

	Dimensions (in mm)

Features

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 RE 280 MKII 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 RE 280 MKII. Due to this facility there is no need for a technician to service the RE 280 MKII 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 RE 280 MKII 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 RE 280 MKII completely, and activated whenever a malfunction is detected. Once the Protection is activated, the RE 280 MKII is powered down.

Frequency Response:

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

Interfering Signal Spectrum @ 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:

The total harmonic distortion curve is very linear, increasing only slightly at the lowest frequencies.This performance is only possible using a highly specialist output transformer.

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