Octave MRE 220 SE, Руководство пользователя

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1. DESCRIPTION OF THE MRE 220 SE
The history of the Octave MRE mono power amplifiers goes back to 1994. The first series was called
MRE 120. From the beginning, the idea behind this development was to develop tube power
amplifiers that would transfer the charm of the tube to a variety of loudspeakers. Therefore, dynamics,
pure performance, bandwidth and absolute stability are the prerequisites to achieve this goal. A key
feature of this new series of mono power amplifiers was the development of our advanced pentode
circuit. This design found its way into all of our top amplifiers, including the Jubilee series.
The MRE 120 received a lot of praise and was replaced in 2004 by the further development MRE
130. 10 years of experience with the 120 made improvements in detail and refinements in the design
possible. 9 years later, in 2013, a major overhaul was undertaken. The newly developed KT 120
power tube enabled more power reserves and an even greater bandwidth of the power amplifier.
Long listening tests with a newly developed output transformer and power supply led to the MRE
220:
Their special properties are extremely high reliability with the highest tonal finesse. The MRE 220 is
the optimal power amplifier for an unusually wide range of combinations. Whether in BI amping with
horn systems or solo with a variety of top speakers on the world market: the MRE 220 is rock solid.
Now, again 10 years later - the next step: The MRE 220 becomes the
MRE 220 SE . Many new
loudspeaker concepts with high resolution in the midrange and the triumph of high-resolution digital
formats lead to an unprecedented quality of playback. Despite all efforts, developing a power
amplifier that harmonizes perfectly with all loudspeakers is - as experience shows - almost
impossible. The requirements of the loudspeaker are too different in terms of power delivery,
bandwidth and, as can now be seen, also the damping factor (or negative feedback) of the power
amplifier.
In listening tests with different loudspeakers, variable negative feedback with an impact on the
attenuation factor emerged as an important new tool.
With this absolutely unique adjustment option within the power amplifier, the interaction of the
MRE
220 SE with speakers can be optimized almost perfectly. The MRE 220 SE therefore has a switch
with which you can choose between the damping factor low and high (or negative feedback low and
high).
This is a completely new approach to the problem of a power amplifier that has to cope as well as
possible with all speakers available on the market. However, the result speaks for itself: an incredibly
clear, spacious reproduction with a perfectly embedded midrange, free of any impurities and a silky
beautiful tonal balance, and this with (almost) all speakers
Short technical explanation:
Damping factor and negative feedback are the subject of controversial discussions. They are
usually discussed independently of each other. In fact, these two properties of a power amplifier
are dependent on each other. A high damping factor can only be achieved through high negative
feedback. Conversely, a low negative feedback inevitably results in a low damping factor. It is
often thought that a high damping factor is responsible for controlled bass. However, practice
does not confirm this assumption. However, it is largely undisputed that a high level of negative
feedback has an influence on the sonic properties of an amplifier. However, the damping factor
has a significant influence on the balance of the playback. Due to high fluctuations in the
impedance of a loudspeaker, the level at certain frequencies can be excessive if the damping
factor is very low. The middle tone, for example, is then reproduced a little too prominently. This
puts the supposed advantage of low negative feedback into perspective.
A higher damping factor helps here. But there are also loudspeakers, usually so-called high-
efficiency systems with an efficiency of 92dB or more, which, due to their principle, require a low
attenuation factor for their top sound.
In the
MRE 220 SE , the optimal negative feedback was found for both damping factor settings,
which eliminates the influence of the higher negative feedback. The switching is so refined that
the gain of the power amplifier is almost identical in both positions. This means that there are no
volume differences when switching, which is particularly helpful with bi-amping combinations