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conventional “Ultralinear”. Triode amplifiers are
generally more tolerant of difficult loudspeaker loads.
How different the sound is in your system will depend
upon your speakers and other factors. Generally
people find it a little smoother and easier to listen to.
Leaving the amp switched on
We are often asked if the amplifier should be left
running 24/7 without switching off. Whilst the
amplifier will sound at its best when it is properly
warmed up, there is no advantage leaving it switched
on when it is not in use. It is using electricity and as
valves have a finite life. Use the Standby switch
when not continuously in use, to avoid switching on
and off unnecessarily.
Standby switch
This switch leaves the valves heated but without
power. This
prevents “Cathode stripping” at switch
on, allows the cathode chemistry to re-form,
minimises energy usage, and makes the amplifier
available for instant use. However as a general guide
it is not recommended that this mode should be
continuously used for more than 24hrs.
We would always advise that any item of home
electronics is switched off when unattended.
‘Burning in’
Although the amplifier should sound good within
about 10 mins it can take up to an hour to sound at
its best and will take several months of regular use
before it is fully
‘run in’.
Upgrading Valves!
Quality valves should sound better and have a better
service. The valves supplied with selected models
are the result of careful comparison with other
makes.
But beware of paying a premium for “New
Old Stock” valves where you may be paying for rarity
value and not performance. Icon Audio normally keep
a range of upgrade valves in stock. As the
manufacturer we have wide experience of all types of
valves, which we are happy to recommend for your
amplifier. For output valves other than KT150/120s
see section 6.
Cabinet Care
To remove dust we suggest gentle brushing of the
polished stainless steel cabinet with a soft
paintbrush. Other marks can usually be removed with
a damp cloth. The Perspex valve cover may need a
gentle wipe with soapy water and drying with a
duster. Never use anything wet on the amplifier, and
always clean with the power disconnected.
5 Trouble Shooting
Amplifier Dead
Check the 3 amp mains fuse (5a USA) at the back of the
amplifier. To gain access, remove the mains lead. The
fuse is in a small plastic drawer, which forms part of the
socket assembly. To open insert a flat blade screwdriver
or similar and prise open.
The fuse in use is the
innermost
the outer is a spare. Should the replacement
fuse also blow there is a fault you should disconnect
from the mains and seek qualified help or Icon Audio.
Replacements should be 3
Amp ‘anti-surge’ (5a USA).
The fuse in the wall plug should be a 3 or 5 amp fuse,
although unlikely to fail, this should be checked if the
amplifier fuse is OK.
No sound
Have you selected the right input? Is the
“Tape Monitor”
switch up? Are all the connections OK? Is everything
switched on? Are the speakers connected?
Distorted sound.
Could it be your source? The speakers or the amplifier,
check all wiring, and try swapping things around to
eliminate or prove which component if the problem.
Left or right amplifier? If both probably the source unit.
Try another source. If one amplifier is distorted check the
bias. No bias reading means either a fuse blown or a
faulty valve. Distorted sound at higher volumes may be
because one of the output KT150/120 valves is not
working. This could be due a faulty KT150/KT120 valve
or one of the KT150/120 internal fuses blowing. A
symptom of this would be no bias voltage showing on
the meter. Also the valve would not be as hot as the
others. Refer to an engineer or to Icon Audio. Spare
internal fuses are secured inside the chassis.
Replacements are available free of charge from Icon
Audio.
Hum Problems
If you experience hum, try disconnecting all inputs, if
hum persists this is probably an amplifier fault.
If not, identify which input is causing hum. Connect
one input at a time. A
common cause is a ‘hum loop’
caused by having too many earths, and may be
identified by unplugging each input source from the
mains. One remedy for this is to use an interconnect
which only has the screen connected at one end.
Other causes of low-level hum can be from adjacent
equipment, so experiment with moving equipment
around to see if this makes the hum better or worse.
Strange noises coming from speakers
Turn volume to minimum on unused input, if the
noise disappears, the fault is with the source or the
connection. If noise persists, the problem is with
amplifier.
If a whole output valve glows red (other than the
heater), often accompanied by a hum through the
speakers, switch off immediately, and refer to Icon
Audio or a service engineer, as this could be valve
failure.
Service:
Should you suspect a problem, you could
return the unit to your dealer or Icon Audio for a
periodic service or return the valves for testing free of
charge. You should carefully remove the valves (the
KT150/120s should be held by the base when
removing, to prevent damage) numbering them with
a marker from left to right as you do so in order that
that may be replaced in the same position. They
should be well packed in cardboard & foam or
similar, and returned to Icon Audio for testing.
(Valves are very rugged if packed properly).
Mains Supply
This amplifier is hard wired to work on 220-240v 50-
60Hzac. The transformer may be re-configured for
115-120v ac by a qualified engineer. Contact for
more information. The IEC fuse will need to 2x
higher.
