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MB 25
Valve Power Amplifier User Manual
Contents
1 Introduction & Final Inspection
2 Quick Set Up Guide
3 Connecting inputs & outputs
4 Getting the best out of your
amplifier
5 Trouble Shooting
6 Specifications
7 Valve Replacement
8 Guarantee
9 Packing Instructions
About the MB25
Thank you for purchasing one of our amplifiers, a lot
of care has gone into the design, selection of
components and production of this amplifier.
In order to get the best out of your MB 25, please
read the enclosed notes. We have tried to give you
all the basic information you will need.
We would
recommend that everyone follows the ‘quick set
up guide’.
Should you be uncertain about anything
to do with your MB 25 please contact us.
The MB 25 are mono-block power amplifiers
designed to complement high quality valve or
transistor pre-amplifier. They require an input voltage
of 1.9v (sine wave) to achieve full output. You may
be able to achieve this with a passive pre-amp or
direct from a CD player with a built in volume control.
One of the beauties of valve amplifiers is that they
are usually very simple; therefore with the use of
traditional point-to point construction and modern
high performance, low tolerance components, it is
possible to very high sonic performance.
The simplicity of the design means that we were able
to avoid the use of printed circuit boards, which are
not ideal for valve amplifiers despite their common
use.
Although good frequency response, low noise and
distortion are important in any hi fi unit, there are
several other criteria that are often forgotten.
Transistors have a poor overload capability, and the
resulting distortion is very unpleasant. The MB 25
has a massive overload capability and even then
would go into ‘soft clipping’, which is more benign
and easier on the ear.
The simplicity of the circuit means that there are
much fewer components for the signal to pass
through, fewer connections and switches, again
adding to the purity of sound.
This simplicity also means that we can use higher
quality oversized components, such as 2w resistors
when ¼ w would do.
The use of popular valves, which are still in
production, means that obtaining replacements is
easy and inexpensive when necessary.
In the process of building the MB 25 to its high
standard no corners have been cut and we have also
paid close attention to the appearance. Stainless
steel has been used for its many properties including:
non-magnetic, non-resonant, non corroding and
attractive. A painted steel sub chassis has been used
to mount the valve holders and smaller components
on. The steel transformer cover uses crackle finish
enamel. The front and back panels are anodised
alloy plate for rigidity.
The final result is an amplifier with excellent
characteristics, with an accurate yet smooth and
transparent quality.
Содержание MB 25
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