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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 e.g. CD, Tuner, Tape Deck, Mini Disc, TV,
Video Recorder, DVD etc having an output of
300mv or more, to get full power.
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 ST40 is a
power amplifier with a volume control, the volume
control will be virtually invisible to the pre-amplifier
if it is the full clockwise position. If you have to
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 40i Classic 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 40i
Classic 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 40i is designed to work with full
range, medium to high efficiency having
impedance of 4 ohms to 8 ohms. Speakers having
efficiency of lower than 86db 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.
Speaker impedance.
It is important to use the
correct speaker impedance terminals, as this will
give the best sound quality and power matching. If
using 15-ohm speakers use the 8-ohm
connections. If you are unsure or “6 ohms” or “4 to
8 ohms” is quoted; a rule of thumb guide is to try
both positions. The loudest being the best match.
Although your personal taste should be the final
deciding factor.
Do not connect to more than one pair of terminals
for each channel. If two pairs of speakers are
required to be connected, they must both be 8-
ohm and connected 4 ohm terminals. Contact
Icon Audio for more information. Damage could
be occur if care is not taken.
