NAD 7125 User guide

NAD

1. Antenna Term inals 6. Speakers
2. Phono
In put
7.
Speaker Im pedance
3. Phono Ground B. AC Power Cord
4. Aux Input 9.
AC Convenience Outlet
5.
Tape Rec/Play (Not in U.K. model)
3 2 4 5 6 7
1 9 8
1. Power 9. Tape Monitor
2. Phones
10 . Input Selector (Aux, Phono, AM , FM )
3. Bass
11 . Tuning Pre-sels
4. Tre b le
12. Up /Down Tuning
5. Balance 13. Memory Enter/Mono
6. Volume 14. Tuning Display
7. Loudness Compensation 15.
FM Stereo Beacon
8. Bass Equalization 16. Power Indicator
16
15 14
2 3 4 5 6
789 10 11
12 13
2

REAR PANEL CONNECTIONS
1. ANTENNA TERMINALS. This receiver is equipped
with four antenna terminals; each is a threaded metal shaft
with a plastic thumbscrew and a toothed washer which
will make secure contact either with bare wire or with the
U-shaped metal spade lug that is often provided on antenna
wires. If you are using an antenna whose lead-in wires have
some other type of connector, cut it off and strip off enough
insulation to expose approximately 1 cm
(V , inch) of bare
wire on each conductor . To connect the antenna wire,
unscrew the appropriate thumbscrew, place the spade lug
or bare wire underthe toothed washer, and turn the thumb-
screw clockwise until it is tight. The toothed washer will grip
the lug
or wire, making a connection that is secure both
electrically and mechanically.
AM. Some form of external antenna will
be needed
for satisfactory reception, since the rece iver does not have a
built-in AM antenna. For most local broadcasting stations a
simple wire up to one meter (three feet) in length will provide
ample signal strength, and such a single-wire antenna
is
included with the receiver. Connect one end of the wire to the
AM terminal. The remainder
of the antenna may be allowed
to hang down behind the receiver or may be tacked in place
horizontally along the rear of a
wooden-not metal-shelf.
(A metal shelf may interfere with reception; in that case the
wire should be stretched out along the wall away from the
shelving and tacked in place
.) You may wish to experiment
with the orientation
of the AM antenna, in order to find the
pOSition that provides the best reception of the stations you
listen to most often.
The short-wire antenna usually will provide satisfactory
reception
of local AM broadcast stations. But if you wish to
improve reception
of distant AM stations, attach a long-wire
outdoor antenna to the AM terminal. As its name implies, a
"long-wire" antenna is a simple, straight wire whose leng th
may be anything from a few feet up to about 100 feet (30
meters), mounted parallel to the earth and as high as is
convenient. In some cases the effectiveness of a long ·wire
antenna will be improved by connecting a second wire
from the Ground (G) terminal to a true earth-ground, i.e.,
a copper-plated rod driven several feet into the earth.
A substitute electrical ground
may also prove effective:
a cold-water pipe, a steam radiator, or the third hole
of a modern electrical wall socket.
FM.
Some form of external antenna must be connected
to the receiver for effective reception of stereo FM broad-
casts. A ribbon-wire "folded dipole" antenna is supplied with
the receiver to
get you started. When you stretch out the
ribbon·wire antenna you will note that it is in the form of a
"T."
The "crossbar" portion of the T should be stretched out
horizontally and tacked in
place-on a wall, on the back of a
cabinet,
or on the floor. The "vertical" section of the T goes
to the receiver's antenna terminals . Connect its two wires
to the two 3000 input terminals.
In view of the excellent sensitivity of this receiver,
you
may find that the ribbon-wire dipole antenna is all you
need for reception
of strong local stations. But it is not very
efficient at rejecting "multipath" and other forms of FM
interference, and it cannot easily be rotated to optimize its
pickup pattern for best reception
of stations in different
directions. Therefore,
in most cases you should use a better
antenna. The recommended options, in order of increasing
cost, are as follows:
(1) A basic "rabbit-ears" indoor TV antenna without
auxiliary coils
or tuning switches. Electrically, such an
antenna is just another dipole (similar to the ribbon-wire
antenna) with its tuned elements made of solid metal, but
with the advantage that it can be rotated. Stretch out each
of its two arms to a length of 30 inches (75 cm), and orient
3
them horizontally or at a shallow angle upward (less than
45 degrees). The ribbon-wire emerging from the antenna's
base should be connected to the receiver's two
3000
terminals in place of the ribbon-wire antenna supplied with
the receiver. Now, for each station in turn, after you tune the
station you can rotate the antenna for best reception.
(2) A more elaborate rabbit-ears indoor
TV antenna
with a tuning switch. This type of antenna does NOT have
greater sensitivity than the simpler rabbit-ears unit, so if
your problem is that the signals you want to receive are
weak and noisy, then an outdoor antenna is the only effec-
tive solution. But in cities and in large buildings where
signals are strong but are contaminated by reflected "mul-
tipath" signals that interfere with good reception, the tuning
switch on an elaborate indoor antenna may improve recep-
tion by reducing the interference.
(3) An electrically tuned indoor antenna, such as the
Technics Wing or B.I.C. Beam Box. Again, such antennas
usually do not provide any advantage over the simplest type
of "rabbit-ears" unit for receiving weak signals. But where a
strong signal is contaminated
by interference, the antenna's
aiming and tuning controls can reject the interference and
yield cleaner reception.
(4) An outdoor antenna. Even the finest indoor an-
tenna, no matter how elaborate, cannot fully exploit the
capabilities of a good FM tuner. For the lowest noise,
minimum distortion, and largest choice of well-received
broadcasts, an outdoor antenna is the best complement
to a fine tuner.
A roof-mounted antenna has three fundamental advan-
tages. First, its large size yields better sensitivity (pulling in
a stronger signal from the desired station) and a narrower
directional pattern for more effective rejection of multipath
refle ctions arriving from other directions . Second, its location
on a roof or tall mast places it above many sources of
interference-other buildings, passing cars and buses, etc.
Third, the strength of received FM signals is directly propor-
tional to the height of the antenna above the ground.
If you already have an outdoortelevision antenna, using
a splitter to extract
FM signals from it may produce excellent
results. However, many TV antennas are deliberately de-
signed to be relatively weak at FM frequencies in order to
minimize potential interference with TV signals at nearby
frequencies (Channel 6
in the U.S.). You may be able to use
a splitter to extract FM signals from
an apartment building's
master
TV antenna system, but usually this yields poor
results because many master antenna systems have
"traps"
to stop FM Signals.
The best choice is a directional FM-only antenna,
mounted as high above ground as is practical, and sepa-
rated by at least two meters (7 feet) from other antennas,
vert ically and horizontally. A shielded lead-in cable will be
mandatory in most locations, bolh to minimize interference
and to preserve strong signals during years of weathering.
The cable
may be either 75-ohm coaxial or a shielded
300-ohm type. If desired stations are located in different
directions (more than 90 degrees apart), a rotor wifl also
be needed
in order to aim the antenna.
If you are using a 75-ohm coaxial cable (either from
your outdoor antenna or from a master antenna system),
connect
it as follows. First remove any connector that may
have been fitted. Strip off about an inch
(2 cm) of the outer
insulation to expose the shield wiring, fold back the shield
and twist its wire strands together, then strip off a half-inch
(1 cm) of insulation from the center conductor. Disconnect
any antenna connected to the
3000 terminals. Connect the
coaxial cable's center conductor
to the 750 terminal and
connect the coaxial cable's shield wire to the adjacent
ground (G) terminal.

After you have completed all of the antenna connec-
tions , examine them to be sure thai adjacent wires or
connectors are not touching each other, short-circuiting
the antenna signal.
2. PHONO INPUT. This input is designed lor use with
phono cartridges of the moving magnet, induced magnet,
moving flux, and moving iron (variable reluctance) types,
and with "high-output" moving·coil pickups (I.e
., those with
a rated output of
1.0 mVor greater). The input impedance
at the Phono jacks is 47K ohms
in parallel with 100 pF.
Plug the signal cables from your turntable into these
jacks. I! 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 careful to
insert each plug fully into the socket so that the plug's metal
skirt fits tightly over the exterior of the socket.
I! 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. If 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. If 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 tNPUT. 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 lowerjack
is for the Right channel.
5. TAPE RECORD/PLAY. The tape connections
may be used wilh 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
RECORD jacks to the recorder's LINE IN jacks (not to
its microphone inputs).
I! 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 jacks. Disconnect the tape
recorder, connect a cable from the receiver's RECORD
output jacks to the processor's "From Amplifier" main inputs,
and connect another cable from the processor's
"To Ampli-
fier" or "Monitor Output" jacks to the receiver'S PLAY inputs.
Then connect your tape recorder to the signal processor's
own TAPE RECORD/PLAY jacks.
6. SPEAKERS. If 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 electrical-supply stores
in either white, black, or brown
insulation.
If 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.
4
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 hote 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. I! your speakers are easily moved, phasing can
easily be checked. Make the connections to the speakers,
place the speakers face-to-face only a few 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.
I! the speakers cannot easily be set face-to-face, then
phasing must rely on the "polarity" of 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, or8 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 ditterent, 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-
nat 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.
7. SPEAKER fMPEDANCE. The impedance of a loud-
speaker varies with frequency, and in many loudspeakers the
impedance is lowest at the frequencies where the highest
power demands occur in music.
In 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 impedance
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 this receiver
is equipped with a Speaker Imped-
ance selector which you can re-set to increase the availab le
power output into 8 ohms and higher impedances. I! you are
not sure of the true impedance of your speakers, or if you
are connecting two pairs of speakers, leave the Impedance
switch in its 4 OHMS setting.
If 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.
NOTE: In the U.S. and Canada the switch may already
have been pre-set for 8-ohm operation, as indicated by an
orange marker directly below the
"80 " label. If you are using
4-ohm speakers, or two pairs of speakers wired
in parallel,
you should re-set the switch to 4 ohms by sliding the screw
heads
to the right in the following procedure.
Before re-setting the Impedance Selector, tum down the
Volume or switch off the Power. Now, in orderto prevent the
Impedance switch from being re-set unintentionally, it is held
tightly in place by screws located to the left and right of the
switch handle.
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, and an orange marker visible through one of the
slots identifies the setting of the switch.
To set the switch at 8 ohms, slide the screw heads to .
the left end of their respective slots so that the orange
~
e li ghtning flash w it har rowhead . w it hinan equ i latera l
triangle , is intended to alert the user of the presence of
uninsulated " dangerous voltage " within the product 's en c lo -
sure ; that may be of sufficient magnitude to constitute a
risk of electric shock to persons .
marker becomes visible under the " 80 " label. (To re-set it for
4 ohms, slide the screw heads
to the right end of the slots.)
Finally, re-tighten the screws.
If the impedance switch is set to 8 OHMS when you are
using low-impedance speakers, or with two pairs of speakers
connected, the receiver may overheat when operated at high
volume levels. Prolonged abuse of this kind could cause
internal fuses to blow in order
to protect the receiver, in
which case you would have to return the receiver to your
dea l er for service .
8. AC POWER CORD. After you have completed mak-
ing connections to the speakers and to other system compo-
nents, plug the AC power cord into a "live" wall socket.
9. UNSWtTCHED AC OUTLET. (Not in U.K. model.)
The AC power line cord of another stereo component, such
as a turntable or tape deck, may be plugged into this acces-
sory outlet. This outlet remains "live" as long as the receiv-
er's power cord is plugged into a wall socket.
~
e exdamation po i nt with in an equ ilalerallriangle is intended
to aJ ert the user of t he presence of important operat i ng and
maintenance (servic i ng) instructions in the literature
accompanying the appliance.

FRONT PANEL CONTROLS
1. POWER. Depress this button to switch on the reo
ceiver. The green LED above the tuning presets will illumi·
nate when the power is on. To switch the power off, depress
the POWER button again and release it.
If you prefer, you may leave the receiver's POWER
switch permanently engaged and use an external switch
(such as a clock timer) to turn the power on and off.
2. PHONES. Plug stereo headphones in here. The
circuit will provide proper drive signals lor all conventional
stereo headphones regardless
01 their impedance, with just
one exception: electrostatic headphones usually are sup·
plied with an adapter unit which must be connected directly
to the speaker terminals on the rear panel.
When a headphone plug
is inserted into the PHONES
socket the loudspeakers are automatically shut off. If you
want to listen to speakers, you must remove any plug Irom
the socke\.
Belore plugging conventional headphones into the
PHONES jack, turn down the VOLUME control lor salety.
And when you are notlistening
to the headphones it is
wise to unplug them Irom the socket. Otherwise, when not
listening to the phones you might inadvertently turn up the
volume to a level which would feed excessively strong
signals
to the headphones and damage them.
You may freely use headphone extension cables. If you
want to use a headphone Y·connector to drive two headsets
simultaneously, they should be identical models. Connecting
together two headphones which differ widely in impedance
usually will produce a substantial loss of volume in the
headset having the higher impedance (or
in both).
3. BASS. The Bass control adjusts the relative level
01 the low frequencies in the sound.The electrical response
of the receiver is flallest when the control
is set in the detent
at the
12 o'clock position. Rotation of the knob to the right
(clockwise) increases the level of low-frequency sounds,
and rotation counter-clockwise decreases their level. Adjust
it to achieve the tonal balance that sounds most natural
to you.
You will note that at moderate rotations away from
center the effect
01 the Bass control is subtle because its
action is confined to the lowest audible frequencies where
significant energy is seldom found in recordings. Only at
large rotations away from center
is there a sUbstantial boost
or cut
at the mid·bass frequencies which are common
in music.
4. TREBLE. The Treble control adjusts the relative
level of the high frequencies in the sound. The response of
the recei
ver is lIallest when the control is set in the detent
at the
12 o'clock position. Rotation of the knob to the right
(clockwise) increases the level
01 high·frequency sounds,
and rotation counter·clockwise decreases their level. Adjust
it to achieve the tonal balance which sounds most natural
to you.
You will note that boosting the Treble increases the
brilliance and clarity
01 details in the sound, but also makes
any noise more prominen\. Turning down the Treble makes
the sound mellower while suppressing hiss and record
surface
no ise, but too much Treble roll-off will make the
sound dul
l.
5. BALANCE. The BALANCE control adjusts the rela·
tive levels of the left and right channels. A detent at the 12
o'clock position marks the point of equal balance. Rotation
of the knob to the right (clockwise) decreases the level
01
the left channel so that only the right channel is heard, thus
shifting the sonic image to the right. Rotation of the knob
to the left shifts the sonic image toward the left speaker.
6
Ideally the detented center position of the BALANCE
control will be the normal setting. But several common
circumstances may cause unequal balance, requiring a
compensatory off-center BALANCE selling to restore the
most uniform spread of stereo sound between the speakers.
These include unequal output from the two channels of the
phono cartridge, different acoustical environments around
the two loudspeakers,
or simply a listening pOSition that is
closer to one speaker than to the other.
Adjust the BALANCE control
to produce a natural
spread of sound across the space between the speakers,
with any monophonic sound (such
as a radio announcer's
voice) appearing as a phantom image centered midway
between them.
6. VOLUME. This control adjusts the overall loudness
level of the sound. It has no effect on the level of the signals
fed to the RECORD jacks lor tape recording. The VOLUME
control is designed for accurate tracking of its two channels,
so that the stereo balance will not shift noticeably as the
loudness of the sound is varied.
7. LOUDNESS COMPENSATION. Pressing this
bUllon engages a "loudness compensation" circuit which, at
low·to·medium sellings of the VOLUME control, boosts the
low-bass response of the receiver
in order to compensate
lor the human ear's diminished sensitivity to low-frequency
sounds at low loudness levels. The circuit also provides a
slight treble boost to overcome the "masking" of subtle
high·frequency details by background noise. The loudness·
compensation circuit in this receiver is more subtle in its
action, and thus more realistic in psycho·acoustic terms,
than similar circuits in other receivers.
8. BASS EQUALIZATION. This circuit boosts the
lowest bass frequencies, those below 60
Hz . In virtually all
loudspeakers the useful output rolls off at frequencies below
the wooferlcabinet resonance (which typically occurs be-
tween 40 and 70 Hz). The BASS EO circuit compensates for
this roll-off, extending the useful response
of the speakers
significantly lower in frequency.
Of course very low frequencies are not found in all
music, nor in all recordings, so the effect of the bass equal-
ization often won't be obvious. Sometimes you may find that
switching it in and out does not produce any noticeable
change in the sound whatsoever, simply because the record·
ing contains no energy atvery low frequencies. But if your
loudspeakers are capable of reproducing low bass, and
if
you play recordings in which low bass does have an impor·
tant role, the BASS EO will make an audible (and occasion-
ally dramatic) difference.
If your loudspeakers already have extended and
powerful deep·bass response, the BASS EO will still be
useful to correct for the bass roll-offs engineered into some
recordings. It also works well
in combination with the LOUD-
NESS COMPENSATION circuit to restore subjectively Ilat
frequency response when you listen to music at low
volume levels.
CAUTION: Be prepared to switch off the equalization
when playing recordings (especially digitally mastered
discs) that contain unusually potent recorded bass. The
BASS EO boosts deep bass levels by 5 dB, i.e. by a factor
of three in power. If this boost
is combined with high·volume
playback levels, a bass·heavy input signal may overdrive
the amplifier into Clipping
and-more important-overdrive
a small woofer beyond its safe excursion limits, causing its
voice·coil to clatter against the magnet backplate. As long
as the speaker sounds good
it probably is OK; but distorted
or unmusical sounds , such as clattering noises , are a sign
of distress in a woofer.
Be alert, also, for signs of acoustic feedback (in which

the low-frequency vibrations from the speakers are picked
up by the record-playing stylus and are re-amplified). If
you encounter a sustained low~frequency roar, or frequent
groove-jumping, immediately turn down the Volume and
switch off the BASS
EQ until a more nearly vibration-free
mounting for the turntable
is found.
9. TAPE. When this button
is pressed it overrides the
other Input Selector buttons and lets you hear the playback
Signal from your tape recorder (or any other device con-
nected to the PLAY input jacks on the rear panel of the
receiver).
If you have a signal-processing accessory (such
as a graphic equalizer or dynamic expander) connected to
the TAPE RECORD/PLAY jacks, pressing TAPE allows you
to hear the processed signal.
CAUTION: If you have nothing connected
to the RE-
CORD/PLAY jacks,
or have a tape deck connected but not
running, then when you press TAPE you will hear nothing
but
silence-regardless of what other selector buttons you
may press!
To disengage the tape monitor circuit and restore
the normal signal path, press the TAPE button again and
release
it.
The standard purpose of the TAPE monitor is to allow
you to listen to recorded tapes, and also to check on tape
recordings as they are being made. If you have a three-head
tape deck that allows off-the-tape monitoring during record-
ing, engaging the TAPE monitor switches on both the re-
ceiver and the tape deck will let you hearthe playback signal
from the tape immediately after
it is recorded, so that you
can check on its quality.
To make tape recordings on a recorder attached to the
receiver's RECORD/PLAY jacks, simply use the INPUT
SELECTOR buttons to select the program source that you
want
to record from (PHONO, FM, etc.). The recording will
not be affected by any of the controls located to the left of
the INPUT SELECTOR; thus you may vary the volume,
balance, tone controls, tape monitor switch, etc
., without
altering the recording that is being made.
COPYING TAPES: If you want to copy a recording from
one tape deck to another, connect the playback cable from
the "source" deck (the machine containing the tape to be
copied) to the receiver's AUXiliary inputs, and connect the
"copying" or "dubbing" recorder to the receiver's RECORD/
PLAY jacks. Press the AUX button in the Input Selector
group to hear the source tape and feed its signal to the
copying recorder.
If you then press the TAPE monitor, you
will hearthe chosen signal after it has passed through the
recorder's electronics.
10. INPUT SELECTOR (AUX, PHONO, AM, FM). These
interlocked switches select the input signal for the receiver.
This is the signal that you will hear, assuming that the TAPE
monitor is disengaged. The selected input signal will also be
fed out through the RECORD jacks for tape recording or
signal processing, regardless of the setting of the TAPE
monitor switch.
11. TUNING PRE·SETS. You can store the frequencies
of ten favorite stations
(5 FM and 5 AM) in these pre-sets
and then tune them instantly just by pressing the appro-
priate button.
The pre-sets preserve their frequency assignments
when the receiver
is switched off or unplugged from the AC
wall socket, for a period of up to two weeks. Thus you can
re-arrange your stereo system, or move the receiver from
room to room, without losing the pre-set frequencies. But if
you leave the receiver switched off for a month or more, you
may have to re-program the tuning pre-sets.
12 . UP/DOWN TUNING. The tuning control is a
"rocker" switch that allows you to tune up and down the AM
or FM radio spectrum. Depress the right-hand section of
7
the switch in order to tune to higherfrequencies, and
the left-hand section
to tune to lower frequencies.
When the TUNING button
is pressed momentarily, the
tuned frequency
is shifted up or down by one step. (In North
America the size of this tuning step
is 10 kHz on the AM
band.
In Europe and elsewhere the luning step is 9 kHz on
AM.
In both cases the tuning step for the FM band is 0.05
MHz.) Each time the TUNING button is tapped, the tuned
frequency will shift up or down by this increment,
as shown
on the digital frequency display.
If the TUNING button is held down with continuous
pressure rather than just tapped, the tuning pauses briefly
and then scans rapidly up or down in frequency.
Thus,
to manually tune a station, the procedure is to
press continuously on either side of the TUNING button until
the receiver's frequency
is close to Ihe desired broadcast
frequency, and then fine-tune by tapping the TUNING button
until the digital frequency display exactly matches the sta-
tion's broadcast frequency as listed in a local newspaper
or broadcasting gUide.
On
FM the decimal point in the digital frequency display
serves as a center channel indicator. It blinks on and off as
you approach the correct frequency, remaining continuously
illuminated when the receiver is tuned to the center of the
broadcast channel.
13. MEMORY ENTER/MONO. This button is used to
enter the frequencies of your favorite stations in the receiv-
er's ten memory pre-sets (five pre-sets on the FM band and
five pre-sets
on AM). The procedure is as follows.
(1) Decide which station you want to assign to each
pre-set. On each band you may arrange the stations in
any order that you find convenient (or easy to remember):
alphabetical
(1 = WABC, 2= WCBS, 3 = WNYC .. ,), numer-
ical
(1 = BBC1, 2= BBC2, ... ), or in order of increasing
frequency
(1 =89.7, 2= 90.9, 3 =95.3, etc). If you are not
certain of the exact frequencies of the stations, check the
station/frequency directory
in a local newspaper or broad-
casting guide.
(2) Select the AM or FM band, as appropriate. Using
the TUNING rocker, manually tune
to the first station on
your list. Press ENTER, then press Pre-set #1 to store the
first station. After you press ENTER you will have almost
ten seconds during which you can store the tuned station
in one of the pre-sets, before the ENTER mode automatic-
ally de-activates.
(3) Manually tune to the second station on your list.
Press ENTER button and then press Pre-set
#2 to store
the second station.
(4) Manually tune
to the third station on your list, press
ENTER, and press Pre-set
#3 to store the station. Continue
in this manner with any other stations that you want to store
in the remaining pre-sets. Then switch to the other tuning
band (FM or AM) and repeat the process for the second
set of five pre-sets.
Incidentally, if you make a mistake or change your
mind, it is not necessaryto re-program all five pre-sets in
sequence.
You can re-program any pre-set at any time:
simply tune to the desired frequency, press ENTER, and
press the pre-set button that you want to re-program.
After you finish programming the pre-sets, you may
wish
to post your list of stations and associated pre-set
numbers near the receiver for reference.
CAUTION: When using the receiver, be careful not to
press the ENTER button by accident. Doing so will activate
the ENTER mode, and if you then press any of the pre-set
buttons you will unintentionally re-program that pre-set.
You
would then have to manually re-tune to the station you

wanted, and re-ENTER it into the pre-set. If you accidentally
press ENTER, you can force the tuner
to back out of the
ENTER mode by tapping the manual TUNING rocker
or by
switching luning bands (i.e. from FM to AM and back).
MONO. The ENTER button has two additional special
functions. One of these is a mono/stereo switch for the
FM
tuner. If a stereo broadcast signal is too weak for reasonably
noise-free reception, the receiver
is designed to switch
automatically into mono. But if you disagree with the factory
setting of this stereo switching threshold, or if varying recep-
tion conditions cause the tuner to switch in and out of stereo,
or if the signal is strong but severely distorted because of
multipath interference, you can lock the tuner
in mono by
pressing the ENTER button, holding
it in for at least two
seconds. Under adverse conditions mono reception will
normally be quieter and more distortion-free than stereo.
(Of course using the ENTER/MONO button to switch
into mono also engages the ENTER mode. The ENTER
mode will automatically disengage within ten seconds. Do
not press any of the station pre-sets during that interval: if
you do, the currently-tuned frequency will be programmed
into that pre-se!.)
The ENTER/MONO button switches only the
FM tuner
into mono. The Phono, Aux, and
Tape inputs are unaffected.
If you re-tune to a different frequency, or switch to a
different input and then back to
FM , or turn the receiver off
and later turn it on again, the tuner automatically returns
to
its normal operating mode in which stereo or mono reception
is selected automatically. You can also return it to automatic
mode by again depressing the ENTER/MONO button for at
least two seconds.
FAST SCAN. The ENTER/MONO button also serves as
an "accelerator" forthe
Up /Down Tuning rocker. If you press
both the ENTER/MONO button and the TUNING rocker, the
tunerwill scan up
or down in frequency approximately five
times faster than normal, moving through the entire FM
tuning band in a few seconds. The usual caution applies,
however: if you press any of the station pre-sets within ten
seconds after pressing ENTER, you will re-program that
pre-set-unless you first disengage the ENTER mode by
using the TUNING rocker in its normal slow-scan mode.
14. TUNING DISPLAY. The display shows the broad-
cast frequency to which the receiver is tuned. (When you
select the AUX
or PHONO input the display is turned oft.) On
the FM band the fifth digit will be either a or 5 since tuning
occurs
in increments of 0.05 MHz. The decimal point in the
display blinks to indicate off-center tuning. (See paragraph
12. UP/DOWN TUNING)
15. FM STEREO BEACON. This red LED illuminates
when a stereo
FM broadcast is being received and decoded
by the receiver's mulliplex decoder circuit. If a station is
broadcasting in mono, or if a stereo broadcast signal is too
weak for reasonably noise-free reception in stereo, then the
receiver will automatically switch into mono and this light will
not illuminate. Also, if you have mistuned the receiver away
from the center of a station's broadcast channel, the stereo
decoding circuits may not lock onto the signal and
it may
be received in mono.
16. POWER INDICATOR. This green LED illuminates
whenever the receiver is turned on .
A Note on Overload Protection. Because the NAD
7125 sounds so clean and musical when driven beyond its
nominal power rating and when used to drive low-imped-
ance loudspeakers, you may be tempted to stress it beyond
its design capacity. For example this receiver can safely and
cleanly drive a 2-ohm load impedance, reproducing wide-
range musical signals wilh peak levels of 50 watts or more.
Thus
it is permissible to play music at volume levels which
cause the transient peaks and climaxes
to exceed the
receiver's rated power
by a considerable margin.
But if you overdrive the receiver continuously rather
than only on brief musical peaks, the output transistors may
overhea!. This
is particularly likely if you set the SPEAKER
IMPEDANCE switch to 8 OHMS and then try to drive very
low impedances at high volume levels. Severe abuse of this
type could cause internal fuses
to blow in order to protect
the receiver. These fuses are not intended to be replaced
by the user: if the receiver shuts down you should return
it for service .
If this occurs, you should examine whethe' a oattern
of unintended abuse may have contributed to the failure.
For example you may have a loose strand of speaker wire
causing a partial short-circuit either at the speakers
or at the
receiver's speaker terminals. The impedance of your speak-
ers may be lower than you think: if you are not sure, set the
SPEAKER IMPEDANCE switch to 4 OHMS.
You may be
combining maximum bass boost with high volume settings.
Or you may simply be playing Ihe music at continuously
high power levels that demand a larger amplilier.

ELECTRONICS
LONDON/BOSTON