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Quick Set Up Guide - icon Audio MB90 MK IIm Instruction Manual

Mono block amplifiers

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IMPORTANT READ THESE NOTES THROUGH FIRST!
1 Unpack 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.
2 If Necessary fit the valves, or check that they are
firmly in place. Fit the valves according to the
numbers written on the base, normally L 1-5 and R
1-5 as printed on the copper plate. The KT150/120s
should be fitted first to the two REAR sockets (the two
sockets nearest the transformers). To avoid damage to
the valves hold the valves as close to the base as
possible
NOTE
THE
"LEFT"
orientation on each amplifier. Also keep the left and
right
amplifier
valves
amplifiers can be identified by the red or black ring
on the input sockets at the rear.
Be careful to note the correct orientation of the
central "spigot" between the pins otherwise damage
3
could occur.
The small valves should be gently & firmly pushed into
place. The 6SL7 (6188) is fitted to the right hand base
(the same side as the triode switch) and the 6SN7 to the
left hand base (the same side as the standby switch).
The 0D3 should be in the centre.
NOTE: The KT150/120's and 6SL7/6SN7 are NOT
interchangeable! This will result in damage and
4
could be dangerous.
3 Connect to source unit, e.g. Phono pre amp,
Passive pre amp etc via appropriate phono sockets. Set
L & R SENSITIVITY switches on the rear to High (H) or
Low (L) as required, see 6a.
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 230v supply. If for some reason the welded
plug must be removed, please remove plug fuse
and dispose of immediately. (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 Before switching on make sure that the "standby
switch" is in the "up" position.
SWITCH ON! Leave for at least 60 seconds for the
valves to warm up, and then push the "standby" switch
into the "down" position. The amplifier should now be
working. Most 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. We recommend

2 QUICK SET UP GUIDE

and
"RIGHT"
KT150/120
separate.
The
right/left
2
5
6
you switch to "standby" when switching off, (to be
ready for your next session).
1
6a High/Low Sensitivity Switch (on rear)
The LOW sensitivity position is designed to work with
normal valve and solid state pre amplifiers, giving the
best damping factor for "difficult load" speakers,
(normal feedback).
The HIGH sensitivity position is for "Passive" pre-amps
(without gain) or devices with a volume control (our
PS1/PS3 phono stage, MP3, "i Phone/Pod" etc).
Purists may prefer this low feedback sound. Feel free
to change and choose your preference.
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.
All these things are normal for valve amplifiers:
A, Valves can get very hot, BEWARE!
B, The power transformer cover will get quite warm
C, The amplifier may smell a little for a few hours.
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.
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 (over
500v DC), 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
household electrical appliances do not leave
unattended whilst switched on. Do not adjust the
KT150/120 bias pre sets without reference to the
manual. Incorrect adjustment could cause the valves
to overheat, with resulting
amplifier.
Bias Adjustment:
The bias adjustment is factory set. No initial
adjustment
suggested that you test after shipping to ensure
the correct operation.
To maintain the best performance of the amplifier
you should check the bias of the output valves
regularly (say once a month). Full details will be
found in section 6.
For use of output valves other than KT150/120 see
section 6.
parts
inside.
in damage to valves and
should
be
necessary.
Like
other
But
it is
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