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3 Connecting inputs & outputs
Many problems associated with electronic
equipment involves connecting leads, which are
usually either
‘BAD CONNECTION’ or a
‘WRONG CONNECTION’
. So it’s worth making
sure that you have good connections and that
your leads are the right way round.
Inputs
The amplifier will work with any standard piece of
hi fi/audio e.g. CD, Phono pre-amp, Tuner, Tape
Deck, Mini Disc, TV, Video Recorder, DVD etc
having an output of 300mv or more.
If you wish to use a turntable you will need a
suitable phono pre-amp. Your dealer or Icon
Audio can advise you. Our new PS1 MM/MC all
valve phono stage is an ideal partner.
To use as a power amplifier.
As the ST50 is essentially a power amplifier with a
volume control, the volume control will be virtually
invisible to the pre-amplifier if turned to the full
clockwise position. If you have too much gain,
“back off” the volume no more than necessary. If
you still have to much gain Icon Audio can modify
the sensitivity to your specification. The tape input
will provide the most direct signal path. Good
quality leads should be used, making sure that
you have good connections both ends.
Connecting a tape deck.
(Or CDRW/MP3 etc)
The STEREO 50 will work with any tape deck
having suitable output, and it is possible to record
from any connected source using the terminals
marked ‘Rec-out’. The STEREO 50 has a ‘Tape
Monitor’ facility, which enables you to use a ‘three
head deck’ or an equalizer, or incorporate into a
A/V system.
Some tape decks present a load to the amplifier
terminals, even when not in use, which can affect
sound quality. (You can do an audible check for
this by removing the plugs and listening for a
change). Therefore for best results do not leave
anything connected to these terminals
unnecessarily.
Connecting loudspeakers
It is important to use good quality loudspeaker
cable. This should be relatively thick and muti-
stranded. i.e. QED ‘Original’ or better. Take care
to connect the correct polarity. The use of
‘Banana plugs’ or ‘spade’ connections will ensure
a good connection whilst minimising the risk of
‘shorts’.
In our experience Icon valve amplifiers are more
tolerant of cables, therefore the benefits of some
very ‘exotic’ cables may be less apparent. But this
is also personal taste.
As all cables have losses, keeping the speaker
cables short is best. It may be better and be
cheaper to re-arrange your room and use shorter
cables than to spend a fortune on longer cables!
You can either ‘hard wire’ your cable to the
amplifier by baring enough cable to fit in the
connector and twist together to avoid any spare
strands touching anywhere else (soldering the
stands together helps).
Be warned this amplifier
does not have an output protection device,
which would degrade the sound. So a
prolonged short due to strands of wire
touching could cause damage.
Alternatively use
good quality ‘banana’ plugs or spade connections,
once fitted they are trouble free.
Speaker polarity. It is essential that you
observe the polarity of the terminals; they
must be the same for the left/right connections
at the amplifier end and at the loudspeaker
end
. Otherwise the sound will be ‘out of phase’
with the sound stage ‘inside out’ with reduced
bass.
If you are unable to check this or confirm
the polarity
(e.g. if you have ‘built in’ wiring), try
the following; Connect the system up and play
some music with plenty of bass (e.g. dance
music), preferably in mono (FM tuners are usually
switchable to mono) and stand the speakers close
together. If correct you should hear plenty of bass,
if not
reverse the terminals for one channel
only, either at the amp or speaker.
You will now
hear more, or less bass. The higher bass output is
the correct setting to use. Another alternative is to
use a test disc. If you are ‘bi-wiring’ your speakers
only two terminals, you must use only 4 or 8
ohms, not both, as this will not load the amplifier
properly.
The STEREO 50 is designed to work with full
range, low to medium efficiency speakers having
impedance between 4 ohms to 8 ohms. Speakers
having efficiency of lower than 84db will have
greater difficulty in providing a high sound level.
But this will also depend upon individual speakers,
room size, type of music and positioning etc.
