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4 How to get the best out of your amplifier
• Do not leave the amplifier switched on all the time. This is not necessary
• Do not switch off and on without a short rest of 60 seconds (to reset the 'soft start')
• Do not adjust the output valve grid bias unless you know how
• Do not swap the output valves round as they are set up individually
• Do not switch from Ultralinear to Triode without switching to Standby or switching off
• Do not operate the amplifier without loudspeakers connected
• Do not use valves other than listed as there could be danger of shock or overheating
• 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 40i MKII 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 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.
Triode Switch. This switch causes the EL34s to
operate as Triode valves. As switching can
stress the output transformers we would
recommend that switching be done when the
amplifier is in "Standby". As the gain the
amplifier is virtually the same the volume is the
same, although at very high volume levels the
dynamics may be reduced and distortion could
occur as full power is half of Ultralinear mode.
Leaving the amp 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. It is using electricity and as valves have a
finite life. Conversely the valves and other
components are stressed more at switch on;
therefore do not switch on and off unnecessarily.
We would always advise that any item of home
electronics is switched off when not in use
Amplifier Dead
Check the 1.6 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
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'.
The fuse in the plug should be a 3 or 5 amp fuse,
although unlikely, this should be checked if the
amplifier fuse is OK.
Standby Switch
This enables the valves to be fully warmed up
before the application of power. Raise the switch
into the "standby" position before switching on and
wait at least 1 minute before lowering the switch
to turn the amplifier "on". In the "standby" position
the amplifier is only using about 30% of normal
power. It also enables a healthy cloud of electrons
to build up around the hot cathode. It also allows
the silver "getter" inside the valve to "mop up" any
gas that has built up inside and therefore keep the
vacuum "hard" for best performance.
'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", valves,
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. On no account use anything wet on
the amplifier, and always clean with the power
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 try different speakers, if no
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.
Page 5
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