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Instruction Manual Covering:
MB90 MK IIm Mono Block
Amplifiers
Shown with KT150 output and upgraded driver valves
Contents
1 Introduction & Final Inspection
2 Quick Set Up Guide
3 Connecting Inputs & Outputs
4 Getting The Best Performance
5 Trouble Shooting
6 Bias Adjustment
7 Valve Replacement
8 Specifications
9 Guarantee
10 Packing Instructions
1 Introduction
Thank you for purchasing the
MB 90s
. These
pure valve mono block amplifiers are the result of
years of careful design and listening tests with a huge
range of speakers. The amplifiers are hand built using
carefully
selected
audiophile
components.
The
transformers are hand would using low oxygen copper
and special Japanese long grain iron. Finally each
amplifier is valved, carefully commissioned and
tweaked for best performance in Leicester UK.
In order to get the best out of your amplifier, please
read the enclosed notes. Even if you are experienced
with hi fi
please read
the ‘quick set up guide’.
Should you be uncertain about anything please contact
your dealer or us for advice.
Valve amplifiers do need a little more attention than
their solid-state counterparts, but the sonic results are
more than worth it. In this manual we have tried to
include everything that you need to know. Please let
us know if you find any errors or feel that we have
missed anything out.
Hi fi reproduction is a long chain of events that
includes the recording, editing, mixing etc, before
being transferred to a medium such as LP, Digital, etc,
before being played through your own source unit, the
amplifier and finally loudspeakers.
Your room acoustics will affect the sound before it
finally reaches your ear. Whilst the amplifier is
arguably the most important part of a system, it is
important to remember that the weakest link will
always affect the final results. And not all recordings
are ‘equal’! Therefore a good amplifier will also
reproduce recording imperfections. Therefore setting
up and testing
should be made with a ‘clean’ well
balanced recording.
The
MB 90
is a push-pull Ultralinear stereo
power amp, capable of running in either Ultralinear
(half pentode and half triode) or pure triode mode,
using the excellent KT150, KT120 valves. These are in
fixed-bias mode which gives maximum power, cool
running and even indicates valve condition. You will
occasionally need to check the bias. The driver and
phase splitting is all triode for best sound quality and
low noise. They are sensitive enough to be used with
all modern source equipment. Their simplicity coupled
with point to point hand wiring without the use of
printed circuit boards results in an open euphoric
sound that is wonderfully detailed and warm.
IMPORTANT!
THIS MANUAL CONTAINS
ESSENTIAL HEALTH &
SAFETY INFORMATION FOR
YOU AND YOUR AMPLIFIER.
PLEASE READ & KEEP SAFE
AND REFER TO IF NECESSARY
