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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 EL34 grid bias unless you know how
• Do not switch from Ultralinear to Triode without first switching off
• Do not swop the EL34's round as they are set up individually
• 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.
• Do use the best possible source material.
• Do use efficient, well-designed speakers.
What is safe maximum volume?
The Stereo 40i 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 EL34's to
operate as Triode valves. As switching can
stress the output transformer we would
recommend that switching be done when the
amplifier is switched off. You will notice that
there is a slight reduction in volume in Triode
mode; this is due to the lower gain that the EL34's
have
in
this
mode,
compensate.
Leaving the amp switched on
People sometimes ask if the amp 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.
Conversely the valves and other components are
stressed more at switch on; therefore do not
switch on and off unnecessarily. We would
Amplifier Dead
Check the 2 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 2Amp
'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.
advance
volume
to
5 Trouble Shooting
always advise that any item of Hi Fi, Video or
TV is switched off when not in use
'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!
This can be a controversial subject, but in our
opinion if a quality valve is operating within its
design specification there is little to be gained in
changing valves. The fitted valves are of excellent
quality and various tests with other expensive
valves both new and old have had inconclusive
results. But we respect that this is a personal
subject and feel free to differ! We welcome
feedback on this matter.
Do not underestimate the quality of supplied
Shuguang brand EL34B this is an uprated version
of the original Mullard design and will therefore
outperform
the
original
replacements made to the original formulae.
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.
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.
design
and
new
Page 5
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