*See engineers notes at rear
Page 5
IMPORTANT READ THESE NOTES THROUGH FIRST!
2 QUICK SET UP GUIDE
Your safety is paramount to us. Big triode
amplifiers like the MB845s operate using high
voltages. Please take care when setting up
and adjusting. DO NOT 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 or
your dealer. It is important that you keep the
packaging for warranty/service return/shipping.
NOTE THE “LEFT” and “RIGHT” 845
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 DIAGRAM.
Fit the valves according to the numbers
written on the base of the valve, and on the
socket, normally 1-8. O
bserve “Left” and
“Right”.
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 push gently but firmly down.
The small valves should be gently but firmly
pushed into place. The 6SL7 (or 6188/6N9) is
fitted to the middle, and the 6SN7 (or CV181/6N8)
to both the left and right positions as marked.
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 they may become
loose/detached. Hold the valves as close to the
base as possible. Damage to valves is not
covered by the warranty. These valves have
already been fitted and tested for quality.
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 (or 120v)*.
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 Neutral terminal and
Green/Yellow to Earth terminal.
6 SWITCH ON!
The meter should light up and the
845s will glow bright yellow. You will likely hear a
“humming noise” for a few seconds, this is normal.
After about 20 seconds the amplifier should now
be working. The small valves may 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 o
ff and refer to the ‘Trouble Shooting’
section or contact Icon Audio.
6a Sensitivity Switch
Located on the rear, this switch
is “UP” (H) for
(high sensitivity) operation. 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 can get very hot, BEWARE!
B, The transformer covers will get quite warm
C, The amplifier may smell for a few weeks.
D, M
obile 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, T
he occasional “click” or “pop” is normal.
I, The hum level may be higher 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 in these
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 845 bias
pre sets without reference to the manual. Incorrect
adjustment could cause the valves to overheat,
with resulting
in damage to valves and
amplifier.
Bias Adjustment:
The bias adjustment is factory set. No initial
adjustment is normally needed.
However you should initially check the bias of the
845 valves to make sure it is correct for your
mains voltage.
Full details will be found in section
6.
