Octave JUBILEE Mono, Руководство пользователя

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1. INTRODUCTION
1.2 JUBILEE MONO SE product description
The JUBILEE MONO SE monoblocs are push-
pull power amplifiers in pentode configuration.
The power amplifiers deliver approx. 400W at 2%
THD.
OCTAVE power amplifiers have always set new
standards.
Andreas Hofmann's RE 280 stereo power ampli-
fier left traditional power amp technologies far
behind when it was first introduced. It goes with-
out saying that this amplifier - like all OCTAVE
products since - was equipped with OCTAVE's
proprietary Power Management and Protection
electronics
POWER MANAGEMENT
The
Power Management
system monitors and
controls the heating and supply voltages at
switch-on. This is tremendously important in
extending the service life of the tubes and
maintaining a consistent sound. It also relieves
the power supply components of the strain of
handling huge surge currents at turn-on.
PROTECTION SYSTEM
Many manufacturers neglect to include electronic
or even passive protection systems in their tube
amps, which means that the life - and indeed the
operational safety - of these amplifiers are greatly
dependent on factors over which the user has no
control. OCTAVE fits its power amplifiers with an
electronic protection system
as a matter of
course.
LOAD STABILITY
The technical breakthroughs that set the original
RE 280 apart were its
optimized input gain
section and its power supply
. Indeed, it used a
totally new power supply design, featuring double
star-grounding and supply voltage isolation. The
optimization of the input stages provided
absolute immunity from influences such as the
loudspeaker load, together with excellent phase
stability for highly accurate push-pull operation
and an extension of the usable frequency range
up to 80kHz. From a sound quality point of view,
these enhancements delivered a consistent tonal
performance and independence from the
impedance response and efficiency level of the
speakers.
PENTODE DESIGN
With the JUBILEE MONO SE power amplifiers,
Andreas Hofmann has gone one step further.
While they have the same power management
and optimized input stage as other OCTAVE
power amps, they benefit from an innovative
and enhanced output stage configuration. What
is revolutionary about this new generation of
amplifiers is that we have 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
design that eliminates the drawbacks of the
classic pentode configuration. This innovative
design involves the use of a second, separate
power supply circuit for the auxiliary current
needed for the pentode mode of operation. The
characteristics of this enhanced pentode circuit
are virtually ideal from both a sound quality and
an engineering point of view. Among the
welcome side effects of the enhanced pentode
circuit
are absolute immunity against
interference and fluctuations in the supply
voltage, and an ability to accept compatible
output tubes.
BIAS
A further effective feature is the
bias
measurement facility
.
Unlike the simpler class-A power amplifier type,
AB amplifiers require adjustment of the negative
grid bias to optimize the idle current for the
power tubes. The setting can change as the
tubes age and it must also be adjusted
whenever tubes are replaced. Normally, this
requires test equipment and knowledge of what
and where to measure, but with the JUBILEE
MONO SE, you can check and adjust the bias
any time the amp is on.
This adjustment has a huge influence on the
sound quality and performance characteristics
of an amplifier (see bias diagram under
Technical data).