icon Audio
Instruction Manual Covering:
MB 805 SE Power Amplifier
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 805
.
These pure valve mono block amplifiers are the
result of years of careful design and listening tests
with a wide range of speakers. The amplifiers are
hand built using carefully selected audiophile
components. The transformers are hand wound
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
“SET UP” notes. These contain important
information about the correct operation and safety.
Should you be uncertain about anything please
contact your dealer or one of our team.
Valve amplifiers do need a little more attention than
their solid-state counterparts, but the sonic results
are well 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.
ABOUT THE SE AMPLIFIER
The MB 805 are Single Ended (SE), this means that
a single valve (805) has to do all the work of both
the “up” and “down” parts of the waveform. In order
to go “down” the valve must be running at 100% of
its
’ maximum power, unlike push-pull amplifiers
where the idle current is very low. Unfortunately the
drawbacks of this system usually means that the
power is limited to a few watts. We overcome the
power restriction by using the very powerful 805
transmitter valve, for SE amplifiers this has the
advantage that it is able to “swing” more negative
than its sister 845.
As the 805 v
alve never “switches off” this gives the
smoothest and most detailed mid range of any
amplifier. This gives 100% Pure
“Class A” power.
The bass and upper treble can be relatively poor
due to the difficulty in making transformers for this
system. The difficulties in transformer design we
have
solved by using our “Tertiary Low Distortion”
transformers that are wound in a complex way by
hand using a third winding to reduce the distortion
generated within the transformer. This makes them
very wide band, with virtually “bottomless” bass.
Running in fixed-bias mode which gives the
maximum power you MUST occasionally check the
bias (say twice a year). The MB 805s are sensitive
enough to be used with any pre-amplifier or a
passive in most situations. 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