Plug the signal cables from your turntable into these
jacks. lf the cables or plugs are color-coded, refer to your
turntable's instruction manual to learn which cable or plug is
for the Left channel and which is for the Right. Be carelul to
insert each plug fully into the socket so that the plug's metal
skirt fits tightly over the exterior of the socket. lf necessary,
crimp the leaves of the plug's metal skirt slightly inward so
as to obtain a tight fit with the socket.
Moving-coil pickups with low output voltage should be
used with an external transformer or pre-preamp. Plug the
turntable's cables into the input jacks of the step-up device,
then connect its outputs to the PHONO jacks.
3. PHONO GROUND. lf your turntable is equipped
with a grounding wire (usually a green wire terminating in
a U-shaped spade lug), connect it to this screw terminal.
Use a screwdriver to loosen the screw, place the spade lug
under the head of the screw, and tighten the screw clock-
wise to secure the lug. lf the grounding wire has no terminal
lug, strip off a half-inch (1 to 2 cm) of insulation to expose
the bare wire, twist the wire strands tightly together, and
fasten the bare wire under the head of the Ground screw.
CAUTION: Do not use excessive force when tightening
the Ground screw, or you may strip the threads.
4. AUX INPUT. These auxiliary jacks are for any "line
level" signal source, such as a television sound tuner, the
audio line output from a videocassette or videodisc player,
or the decoded signal from a digital audio disc player. As
with the other input/output jacks on this receiver, the upper
jack in each pair is for the Left channel and the lower jack
is for the Right channel.
5. TAPE RECORD/PLAY. The tape connections
may be used with recorders of all types: cassette, micro-
cassette, open-reel, digital, etc. To play recorded tapes,
connect a stereo patch cord from the recorder's LINE OUT
jacks to the receiver's PLAY input jacks. To make record-
ings, connect a stereo patch cord from the receiver's RE-
CORD jacks to the recorder's LINE lN jacks (not to its
microphone inputs).
lf you wish to use a signal-processing accessory with
your receiver-such as a graphic equalizer, a dynamic
expander, a DBX or CX disc decoder, a noise filter, or an
ambience-reproduction system-you must connect it to the
receiver's TAPE RECORD/PLAY iacks. Disconnect the tape
recorder, connect a cable from the receiver's RECORD
output jacks to the processor's "From Amplifier" main in-
puts, and connect another cable from the processor's "To
Amplifier" or "Monitor Output" jacks to the receiver's PLAY
inputs. Then connect your tape recorder to the signal
processor's own TAPE RECORD/PLAY !acks.
6. DC OUTPUT This DIN-type socket can provide op-
erating power (+ 17 volts DC) to certain accessory products
such as a pre-preamplifier for low-output moving-coil car-
tridges. Such products might have to be fitted with a plug
that fits this socket.
7. SPEAKERS. lf the wiring to each loudspeaker
will not be longer than about 6 meters (20 feet), then
connections should be made using 18-gauge wire such as
common lamp cord ("zip" cord), available from hardware
and e]ectrical-supply stores in either white, black, or brown
insulation. lf the wiring to the speakers will be longer than
about 6 meters, heavier 16-gauge or 14-gauge wire is
preferred. Heavy-duty wiring is especially desirable if
you are using speakers of low impedance or two pairs
of speakers wired in parallel.
To make connections, separate the two conductors of
the cord, strip off about a half-inch (1 cm) of insulation from
each, and in each conductor twist together the exposed wire
strands. Fully depress the colored tab below each SPEAK-
ERS terminal in order to open up the hole in the terminal,
then insert the bared wire into the hole and release the tab;
the terminal will grasp the wire and hold it in place. Repeat
for each conductor, connecting the wires from the left-chan-
nel speaker to the L+ and L- terminals and the wires from
the right-channel speaker to the R + and R - terminals.
Check to be sure that no loose strands of wire are touching
any adjacent terminal or wire.
PHASING. Stereo speakers should operate in phase
with each other in order to yield a good stereo image and
to reinforce rather than cancel each other's output at low
frequencies. lf your speakers are easily moved, phasing can
easily be checked. Make the connections to the speakers,
place the speakers face-to{ace only a lew inches apart,
play some music, and listen. Then swap the connection of
the two wires at the back of ONE of the speakers, and listen
again. The connection which produces the fullest, boomiest
bass output is the correct one. Connect the wires securely to
the speaker terminals, being careful to avoid leaving loose
strands of wire which might touch the wrong terminal and
create a partial short-circuit, and then move the speakers
to their intended locations.
lf the speakers cannot easily be set face-to{ace, then
phasing must rely on the "polarity" oI the connecting wires.
Note that the SPEAKERS terminals on the receiver are
color-coded: in each channel the terminal with the red tab
has positive " + " polarity and the black terminal is negative
" - ". The terminals at the rear of the speakers are also
marked for polarity, either via red and black connectors or
by labels: " + ", 1, or 8 ohms for positive, " - ", 0, or G for
negative. As a general rule the positive (red) terminal on
the receiver is to be connected to the positive terminal
of the speaker, in each channel.
To facilitate this, the two conductors comprising the
speaker wire in each channel are different, either in the
color of the wire itself (copper vs. silver) or in the presence
of a small ridge or rib pattern on the insulation of one con-
ductor. Use this pattern to establish consistent wiring to both
speakers of a stereo pair. Thus if you connect the copper-
colored wire (or ribbed insulation) to the red receiver termi-
nal in the Left channel, do the same in the Right channel. At
the other end of the wire, if you connect the copper-colored
wire (or the ribbed insulation) to the red or positive terminal
on the left-channel speaker, do the same at the right-
channel speaker.
8. SPEAKER IMPEDANCE. The impedance of a loud-
speaker varies with frequency, and in many loudspeakers
the impedance is lowest at the frequencies where the high-
est power demands occur in music. ln the majority of "8
ohm" loudspeakers this minimum impedance is from 4 to 6
ohms, and in "4 ohm" speakers the minimum is typically 3
ohms. And if you were to connect two pairs of speakers to
the receiver, wiring them in parallel, their combined imped-
ance would be approximately half the impedance of either.
For these reasons, all NAD receivers are designed to
produce maximum power output into impedances of 2 to 6
ohms. But the 7120 receiver is equipped with a Speaker
lmpedance selector which you can re-set to increase the
available power output into 8 ohms and higher impedances.
lf you are not sure of the true impedance of your speakers,
or if you are connecting two pairs ol speakers, leave the
lmpedance switch in its NORMAL (4 OHMS) setting.
ll you are using a single pair of loudspeakers whose
minimum impedance is at least 6 ohms and whose average
impedance is above 8 ohms, you should re-set this switch to
re-optimise the amplifier for maximum power delivery at this
higher impedance.
First, turn down the Volume or switch off the Power.
Now, in order to prevent the lmpedance switch from being
re-set accidentally, it is held tightly in place by a pair of
screws located to the left and right of the switch handle. Use
a screwdriver to turn the screws slightly counter-clockwise
to loosen them. (DO NOT REMOVE the screws!) Note that
the screws are installed in slots so that they can be moved
to the left or right. To set the lmpedance selector to HIGH
(8 OHMS), slide the screw heads all the way to the left end
of their respective slots. Then re-tighten the screws.
