LINE CONNECTIONS AND SWITCHING
The SE120 is normally wired for use on 12OV AC power
lines, as in the U.S.A. If your line voltage is different, you
will need the special Hafler export power transformer
which accommodates many other line voltages. Be sure
your amplifier is wired for your line voltage before you plug
it in.
The SEl2O’s power switch may be left on, and the
amplifier switched remotely by connecting its line cord to
the preamplifier (or other control center) which provides a
switched AC outlet. Make sure that the control device can
supply a current of 5 amperes to the SE 120, in addition to the
current required by any other switched units. You may
instead connect the amplifier directly to a wall outlet, and
control it with its own front panel power switch.
CONNECTING CABLES
GROUNDING:
INPUT:
Conventional shielded cables, often supplied with pre-
amplifiers, may connect the control center to the amplifier’s
input jacks. Be sure the cables are not frayed or loosely
connected to the plugs, and that the plug’s outer shield
connection is tight on the jack, to avoid hum. If you wish to
install the SE120 more than a few feet from the preampli-
fier, the permissible cable length to avoid loss of high
frequencies is determined by the preamplifier’s output im-
pedance and the internal capacitance of the cable. If the
output impedance is 600 ohms or less, as with Hafler
preamplifiers, and the cable capacitance is less than 50
picofarads per foot, up to 50- feet is acceptable. Ordinary
stereo interconnecting cables often have higher capaci-
tance, however, so a good quality low capacitance shielded
wire should be used. When making long runs, keep the left
and right cables close together, and avoid running them
parallel to power wiring to reduce the likelihood of hum
pickup.
OUTPUT:
The wires which connect the speakers to the amplifier
should be of sufficient size to preserve the SEl2O’s high
damping factor.
Standard #18 gauge lamp cord
is satisfac-
tory for up to 15 feet if your speakers are of 8 ohms or higher
impedance. A heavier gauge (
#16
or larger) wire should be
used with 4 ohm speakers or 8 ohm speakers at a greater
distance. Special loudspeaker cables which have adequate
thickness to accommodate long runs are usually available
from audio dealers. The SEl2O’s red and black outputs
accept standard banana plug connectors, including the
double ones with 3/4” spacing. These are the most conven-
ient to use if you will be disconnecting the speakers occa-
sionally. The terminals will also clamp
a
spade lug, or a bare
wire through the hole in the center post. Be sure there are
no frayed wire ends which could touch adjacent terminals
or the chassis. Tin bare wire ends with solder to secure all
strands.
PHASING:
Consistent phase relationships are important when con-
necting speakers in order to enable full bass reproduction as
well as midrange and high frequency time alignment. To
be sure all speakers in a system are wired in phase to the
amplifier, each ground or - speaker terminal should be
connected to its black ground tenninal on the SE 120 and the
sp terminal to the corresponding red binding post.
Speaker connecting cable identifies one wire from the other
by the color of the wire, or by marking or coloring the
insulation. NOTE: In the special case of monophonic
operation of the SE 120, (described later) different speaker
connections are employed.
The black output terminals of the SE120 are connected
together internally and grounded to the chassis. This
facilitates the use of external devices which use a common
ground connection, such as some headphone junctionboxes.
You must be sure that the ground or shield connection from
such a device goes to a black terminal on the SE1 20.
NOTE: No such connection may be made when the SE120
is connected for bridged mono operation.
CONVENTIONAL STEREO
CONNECTIONS
It is best to make all connections with the SE120
switched off. Each of the stereo speakers connects to one
horizontal pair of red and black outputs, as identified left or
right on back of the SE 120. The input signals connect to the
corresponding input jacks, and the mono/stereo switch
should be set to stereo.
CONNECTIONS FOR MONOPHONIC
OPERATION
When you wish to drive a single loudspeaker with
increased power capability, the SE120 can be operated in
a bridged mode which drives both channels with the same
signal and combines their output to deliver more than 120
watts into 16 ohms. In this arrangement, the speaker is
connected only to the two red output terminals. The left red
terminal is + and the right red terminal is the
-
connection.
NO CONNECTIONS MAY BE MADE TO ANY BLACK
TERMINAL!! Set the Input Mode Selector switch to
mono, and connect the input signal to the left channel input
only. IMPORTANT NOTE: Never use a speaker with an
impedance of less than 8 ohms when operating the SE120
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