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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 when not in use. Valve life will be reduced.
•
Do not switch off and on without a short rest of 30 seconds.
•
Do not adjust the output valve grid bias without reading section 6.
•
Do not operate the amplifier without loudspeakers connected.
•
Do not use valves other than listed as there could be danger of shock or damage.
•
Do check the bias regularly at least once a month for best performance.
•
Do make sure the speakers are in phase.
•
Do use the best possible source material.
•
Do use efficient, well-designed speakers.
Siting
The amplifier should be placed on top of a unit or
an open shelf where freely circulates.
What is safe maximum volume?
The Stereo 40 MK IV will run happily all day long
at a high volume; the valves are hardly stressed
any more than at zero volume. Running into
distortion will however stress the whole amplifier.
The maximum safe volume is just before distortion
occurs. However this will vary according to the
level and type of music played.
Triode Mode.
Normally the ST40 6L6 is in "Ultralinear" mode
which means the valves are used in 50%
Pentode, 50% Triode. This give 90% of the power
of pure Pentode with 90% of the characteristics of
pure Triode.
If requested the amplifier may be converted to
pure Triode with about 40% reduction in power.
Headphone Use.
A headphone amplifier may be connected to the
REC
OUT
terminals
whatever the selector switch is set to.
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
which
will
reproduce
when it is properly warmed up, there is no
advantage leaving it switched on when it is not in
use. The valve types used give a fast warm up
and are fully working in 60 seconds.
We would always advise that any item of home
electronics is switched off when not in use
'Burning in'
Although the amplifier should sound good
within about 5 mins it can take up to an 30
mins 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 upgraded valves
supplied with selected models are the result of
careful comparison with other makes. But beware
of paying excessive amounts for "New Old Stock",
second hand valves. At this time we recommend
Genelex, E.H. Tung Sol, Psvane, JJ, which we
are happy to test and supply.
Cabinet Care
To remove dust we suggest gentle brushing of the
cabinet paintwork with a soft paintbrush. Other
marks can usually be removed with a damp cloth.
On no account use anything wet on the amplifier,
and always clean with the power disconnected.
Page 5
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