C H A P T E R 1
Introduction
Congratulations on your purchase of the VTL MB-450 Signature Monoblock Amplifier – an
advanced- technology vacuum tube amplifier engineered for outstanding sonic performance.
VTL is delighted to welcome you as a new owner of our MB-450 Series III Signature monoblock power amplifier. This
precision-engineered high-performance amplifier will provide you with many years of trouble-free listening pleasure.
This newest iteration of the long-standing MB-450 platform is a full re-working of the complete amplifier, with a fully
balanced input stage driving a differential phase splitter and a push-pull output stage with an improved, balanced output
transformer, all combining to bring the sonic performance of the venerable 450 platform to even greater heights. The
Series III also incorporates VTL’s advanced Auto Bias and Fault Sensing technology--features formerly available only
with our flagship Reference products. A revised power supply and improved electronics give the MB-450’s an ultra-fast
transient response and a dynamic range that discerning music and film lovers will instantly notice and appreciate. We
thank you for selecting this amplifier for your home audio/theater system, and trust that you will enjoy its musical
distinction for years to come.
To get the most benefit from your purchase, we recommend that you take time to familiarize yourself with the
features of this product. Please take a few minutes to read through this owner’s manual, as it contains all of the
installation procedures needed to connect your new amplifier to the rest of your system, and details the many
functions that it can perform. After you have finished reading this manual, please put it in a safe place for future
reference.
The Origin of the MB-450 Signature Monoblock Amplifier
The MB-450 Signature Monoblock Amplifier (including its predecessors) has been a core model in the VTL line
for over 20 years. With the release of the Deluxe 300 monoblocks in the late 80’s, VTL successfully introduced a
high power amplifier that could drive a wide range of speakers and yield outstanding performance for a
reasonable price. The model evolved incrementally over the years, including a name change to the MB-450
Signature Monoblocks in 1996.
With the release of the MB-450 Series II Signature Monoblocks in 2007, the Smart Tube Technology first
introduced in the flagship Siegfried Reference monoblocks in 2004 became an essential standard feature in the
VTL Signature monoblock family. This system encompasses logic-controlled automatic biasing--which
continually checks each tube for optimal performance--and an array of fault-sensing diagnostics that alert users
to the operating status of each tube. The "smart tube" technology puts an end to the guesswork formerly
inherent in large tube amplifiers, making the new MB-450s easier to use and maintain. Other technology that has
trickled down from the Siegfried amplifier includes a precision-regulated power supply and upgraded circuitry
components.
The MB-450 Series III Signature Monoblock incorporates even greater technological improvements with the
goal of enhancing the amplifier’s ability to drive a diverse range of speaker types. These include a re-designed
fully balanced differential input stage driving a differential phase splitter and a lower impedance push-pull output
stage with a dramatically improved, fully balanced, interleaved and coupled output transformer. As a result, the
MB-450 has attained new thresholds of sonic performance, with greatly improved bass tightness and dynamics.
MB-450 Series III Signature Monoblock Owner’s Manual
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