Nothing sounds better than the original
 

Every high end device should aim at full-scale reproduction. In the output stage domain, this aim is hard to achieve with classical tube technology. High resolution loudspeakers require stable broadband output stages. This asks too much of tube amps in classical technology. The tonal result in dynamics, bass, fundamental sound and load stability is unsatisfactory. Analysis of these characteristics induced us to throw aboard some essential elements of tube amplifier technology.

This was due to the realization that it does not make sense to optimize a limited system – the limitation itself has to be eliminated. This resulted in our complex hybrid technology. Hybrid technology means that according to task, tubes as well as modern semiconductors are employed. OCTAVE uses the strenghts of each technology which leads to multiplication of the positive characteristics. Our amplifiers now include the following: Power supply unit (engergy supply) / power management / amplifier.

The power supply unit is of great importance for the sound itself and also with regard to dynamics and performance of the output stage. The power supply units are very efficient with extremely low noise, low ripple and low distortion and contain on principle only the best available electrolyte and film capacitors for energy storage. Due to the working principle of tubes – this is essentially the effect that tubes have to be heated slowly and in a well-defined manner before being able to work optimally – the Power Management (PM) is superordinate to the power supply unit as a controlling element. The PM controls and regulates the chronological process of functions: heating – operating voltage – monitoring of all relevant safety functions. Only after stabilization of all parameters necessary for operation of the tubes, PM releases the signal path. This prevents adverse conditions for the tubes during power on/off and also during operation.

Additionally, electronic safety is integrated into the PM. This system constantly monitors the output stage and other important parts of the device. In case of error, the power supply within the device is switched off. In all possible scenarioes, this almost excludes secondary damage inside and outside the device.

The amplifier: The characteristics broadband, low distortion level, stability towards impedance of difficult loudspeakers, linear level control (= dynamics) can be realized with our output stage design. The power supply unit in Zero Impedance Technology ensures the required range, especially for deep frequencies. The fundamental sound is extremely powerful without timing error, as caused by the otherwise usual phase errors. The bass is integrated into the sound event and does not lag behind. We do not believe control and stability of the amp are guaranteed by an extremely high attenuation factor (with respectively high negative feedback), but optimization of the negative feedback in itself is a prerequisite of a stable output stage. If you have stability, you also have the required control. On principle, the output transformers are of great importance. We develop and optimize them for each single device. Together with the amplifier function they reduce the negative feedback factor. Negative feedback is set only as high as required to reach the sound optimum. This makes the output stages in their tonal characteristics almost independent from charge. They can therefore be implemented for a large number of different speaker concepts without sound drifting off.

Service and lifetime: True to the motto „The best car is not worth anything if it does not drive”, we have given more features to our devices. The user can check and correct the BIAS (no-load current) of the output tubes any time by means of the integrated measurement system. This is important not only for running operation: The BIAS-tuning ensures that the tubes always operate exactly on the tonally highest level. Without any problems, new tubes can be inserted, checked and tuned without moving the device. This always insures sound characteristics to 100%.

OCTAVE devices are generally safe to idling and short circuit. Mains oscillations up to 15% are balanced by the electronics of the power supply unit. The PM regulates soft running up of the device after starting. There are no more irritating phenomena when switching on and off compromising lifetime of the device. All these measures result in the very long lifetime of the devices. While the lifetime of the (end) tubes is about 3 to 5 years, the devices themselves have such a long lifetime that you can call them “companions through life". Within this period, in general no service will be needed. Indulgent operation of the tubes will preserve sound characteristics within lifetime of the tubes.

As a result you have extraordinarily sounding amps with extraordinary characteristics: Example output stage MRE 130: Operative range: 130 W from 20 Hz to 80kHz, transfer range at 20 W: 5 Hz – 100 kHz +/-0.5 dB, Interfering signal at LS output: 0.3 mV, stable up to 2 Ohm Speaker impedance, example preamp HP 500 SE line : Asymmetric range : 0.5 Hz - 1.5 MHz -0.5 /-3 dB, Output resistance : 100 Ohm, interfering signal with reference to input signal 1.5 µV (evaluated).

  Oscillogram HP 500 SE noise and ripple spectrum:
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  The noise and ripple spectrum of the HP 500 SE follows the theoretial ideal line and is extremely low at average 2 - 4 µV. Ripple residues are definitely not present.
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Square wave reaction of the line stage of the HP 500 SE:
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  Square 2: HP 500 SE
Square 1: Generator
The line stage is extremely quick with less than 0.4 µs rise and fall time
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Oscillogram MRE 130:
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  FFT analysis of the output signal of MRE 130: linear course of the 2nd, 3rd and 4th upper wave, mains disturbances in the area between 50 and 100 Hz are virtually not present, they are about 0.1 mV
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Square reaction of the power amp MRE 130 at 30 Hz:
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  Square 2: MRE 130
 
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