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4 How to get the best out of your amplifier
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Do not leave the amplifier switched on all the time. This is not necessary
•
Do not switch off and on without a rest of 60 seconds (this could blow the internal 500ma AS fuses)
•
Do not adjust the output valve grid bias without reading the procedure
•
Do not operate the amplifier without loudspeakers connected
•
Do not use valves other than listed as this could be dangerous and damaging to the amplifier
•
Remember to check the bias about twice a year for best performance.
•
Make sure the speakers are in phase.
•
Use the best possible source material.
•
Use efficient, well-designed speakers.
What is safe maximum volume?
The Stereo 40 6AS7 will run happily all day long at
maximum power; the valves are not stressed any
more at full power than at zero volume. Running into
gross distortion will however stress the whole
amplifier. To find the maximum safe volume, play full
range music and advance the volume until distortion
occurs, (this is normally between 12 and 3 o'clock on
the volume control) back off the volume control about
30 degrees, this is approximately full music power.
However this position will vary according to the level
and type of music and the output of the source unit.
For example CD players tend to be higher than say
tuners or phono stages.
Leaving the amplifier switched on
Do not leave the amplifier switched on 24/7. Your
valves will be worn out in approximately nine months!
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. See (Standby
Switch). We would always advise that any item of
home electronics is switched off when not in use
Standby Switch
If the amplifier is not needed for a few hours, it can be
left in the "standby" state. This enables the valves to
be fully warmed and ready to use the instant you put
the standby switch down. In the "standby" position the
amplifier is only using about 50% of normal power. It
also enables a healthy cloud of electrons to build up
around the hot cathode. Also it allows the silver
Amplifier Dead
Check the amp mains fuse in the small drawer in the IEC
mains socket 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 bade 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. Replacements should be 1.6 Amp 'anti-surge'.
Available from Icon Audio free! contact us and we will
post them to you.
The fuse in the UK wall plug should be a 3 or 5 amp
fuse, this should be checked if the amplifier fuse is OK.
If one channel only, has stopped working it is likely to be
one of the two internal left and right HT fuses. There are
2 spares inside. You should refer to your dealer or Icon
Audio if you suspect one of these to have blown. If this is
not possible you should disconnect power for 20 mins,
invert the amplifier on a soft surface and remove the
bottom cover (where the spares are located) and replace
if necessary. If the fuse blows again there is a fault.
Replacement fuses are 500ma AS (or T).
"getter" inside the valve to "mop up" any gas that has
built up inside and therefore keep the vacuum "hard"
for best performance. There is no benefit to leaving
the ST40 on standby indefinitely. If not in use switch
off!
'Burning in'
Although the amp 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!
Good quality new valves sound better, have good
performance and reliability. The upgrade valves
supplied with selected models are the result of
careful comparison with other makes. But beware
paying excessive amounts for "New Old Stock",
second hand or "Fake/copy", valves. At the time of
writing (07.2011) there are good stocks of Russian,
Chinese and US military valves (military number
6080) available. Svetlana and Sovtek are making
new 6AS7s.
Cabinet Care
To remove dust we suggest gentle brushing of the
polished
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. On no account use anything wet on the
amplifier,
disconnected.
5 Trouble Shooting
No sound
Have you selected the right input? Are the
connections OK? Is everything switched on? Are the
speakers connected?
Distorted sound.
Try another source; if sound improves then it's
probably something wrong with the first source. If no
improvement
improvement could be an amplifier problem.
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.
stainless
steel
cabinet
and
always
clean
try
different
with
a
soft
with
the
power
speakers,
if
no
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