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volume will remain virtually the same, but the
maximum output is reduced by approximately
50%. The characteristics of a "Triode" amplifier
are different from the 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.
Amplifier Dead
Check the 3 amp mains fuse 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'.
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 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 KT120 valves is not working.
This could be due a faulty KT120 or one of the KT120
internal fuses blowing. A symptom of this would be no
180mv bias voltage at the test point. 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
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.
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
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
KT120s 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 230/240v ac.
The transformer may be re-configured for 110/120v
ac by a qualified engineer. Contact for more
information.
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