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IMPORTANT READ THESE NOTES THROUGH FIRST!
Your safety is paramount to us. Big triode
amplifiers like the MB845is operate using high
voltages. Please take care when setting up
and adjusting. NEVER OPERATE WITHOUT
VALVES FITTED. If you are uncertain how to
proceed at any point ask your dealer or Icon
Audio.
1 Unpack each unit carefully. Make sure that it
is in good condition. If not report to Icon Audio. It
is important that you keep the packaging for
warranty/service return/shipping.
NOTE
THE
"LEFT"
orientation on each amplifier. Also keep the
left and right amplifier valves separate.
2 If Necessary fit the valves, or check that they
are firmly in place.
SEE PREVIOUS PAGE.
Fit the valves according to the numbers
written on the base of the valve, and on the
socket, (normally numbered 1-10). The 845s
should be fitted first to the two REAR sockets (the
two sockets nearest the transformers). Fit by
locating the bayonet pin at the side and twisting
clockwise by 45 degrees. (For the novice all four
845s should be oriented in the same).
The small valves should be gently but firmly
pushed into place. The 6SL7 (or 6188) is fitted to
the right hand side, and the 6SN7 to the left hand
side (viewed from the front).
Be careful to note the correct orientation of
the small valves central "spigot" between the
pins otherwise damage could occur.
To avoid damage to the valves do not twist the
glass envelopes excessively as the base may
become loose/detached. Hold the valves as close
to the base as possible. Damage to valves is not
covered by the warranty.
3 Connect to source unit, e.g. Pre amp, Passive
pre amp etc via sockets on the rear.
4 Connect speaker terminals use "0" &"8 ohm"
terminals unless you have 4 ohm speakers (see
P5) Make sure that the polarity is correct. (See
speaker connections chapter 3). If 'bi-wiring' both
'common' should go to the black terminal and both
'positive' (or red) should go to the red terminals.
5 Connect to mains supply using supplied IEC
mains lead to 230/240v supply. If for some
reason the welded plug must be removed,
please remove plug fuse and dispose of
immediately. (As they can be a danger to
children if plugged in). The replacement plug
should be wired in the following way Brown to Live
terminal,
Blue
to
Green/Yellow to Earth terminal.
6 SWITCH ON! The blue mains indicator should
light up. The 845s will glow bright yellow. You will
likely hear a "humming noise" for about 20 secs,
through your speakers, this is normal. After about
40 seconds the amplifier should now be working.
2 QUICK SET UP GUIDE
and
"RIGHT"
845i
Neutral
terminal
and
The small valves should have a visible orange
glow from the cathode heaters. With the pre amp
volume control set to minimum there should be no
sound coming from the speakers except a barely
discernable hum. If there are any unpleasant
sounds coming from the speakers, switch off and
refer to the 'Trouble Shooting' section or contact
Icon Audio.
6a Passive/Power Amplifier Operation Switch
Located on the rear, this switch is "UP" for
Passive operation (high sensitivity). Or if use with
a pre-amplifier is required, the switch should be
"DOWN" in the low sensitivity position.
7 Your unit should now be functioning. If not
check wiring again. Do not operate at a high
volume for the first five minutes to allow the valves
to warm up properly.
Please note all these things are normal for
valve amplifiers:
A, Valves will get very hot, BEWARE!
B, The transformer covers will get quite warm
C, The amplifier may smell for a few weeks.
D, Mobile phone 'breakthrough' is normal.
E, Valves may make a 'tinkling' sound when
warming up and cooling down.
F, One channel may come on before the other at
switch on.
G, There may be a 'click' when switching off.
H, The occasional "click" or "pop" is normal.
I, The amplifiers may "hum" for about 30 secs
after switching on.
8 Health and Safety. The valves when operating
have high surface temperatures. Keep out of
reach of children and pets. The use of the
supplied
guard
is
recommended
circumstances. Always unplug when making
adjustments. Like all amplifiers there are
potentially lethal high voltages inside, which
when switched off can take twenty minutes to
discharge! Do not remove bottom panel unless
you are a competent engineer. There are no user
serviceable parts inside. Like other household
electrical appliances do not leave unattended
whilst switched on. Do not adjust the 845i bias
pre sets without reference to the manual. Incorrect
adjustment could cause the valves to overheat,
in damage to valves and
with resulting
amplifier.
Bias Adjustment:
The bias adjustment is factory set. No initial
adjustment is necessary with the supplied
valves.
To maintain the best performance of the amplifier
you should check the bias of the output valves
from time to time (say twice a year). Full details
will be found in section 6.
in
these
Page 4
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