NAD 1020A stereo preamplifier Instructions

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NADIE
PREAMPLIFIER
INSTRUCTIONS
FOR INSTALLATION
AND OPERATION
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3. MM/MC Phono Selector —
4, Phono
5. Tuner
6. Auxiliary Input
В 7. Tape Rec/Play
В. Pra Out
9, Hi-Level Pre Ou
10. AC Ling Card
11. AC Convenience Outlets
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4, Tourne-disques
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22:04:51 20-01-2011
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REAR PANEL CONNECTIONS
1. 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 terminal. Turn the thumbnut counter-
clockwise, place the spade lug under the nut, and tighten the
thumbnut clockwise to secure the lug. If the grounding wire
has no terminal lug, strip off a haif-inch {1 cm) of insulation to
expose the bare wire, twist the wire strands tightly together,
insert the wire through the small hole in the shaft of the
Ground terminal, and tighten the thumbnut to fasten the
wire in place.
2. PHONO CAPACITANCE SELECTOR. This switch
selects the input capacitance, for the PHONO input only.
lt enables you to optimise the load capacitance for those
pickup cartridges whose frequency response is affected by
this parameter. (The input resistance is 47,000 ohms and is
unaffected by the switch.)
If you are using a low-inductance pickup (such as a
Grado or Micro-Acoustics model), or a high-output moving
coil cartridge, or a low-output moving-coil cartridge with a
transformer or pre-preamp, then the setting of the Capaci-
tance Selector is unimportant. But with many high-inductance
magnetic pickups the capacitance setting will alter the high-
frequency tonal balance.
In order to select the best value of preamp input capaci-
tance, you must first learn the total capacitance recom-
mended by the manufacturer for the cartridge. Usually this
will be listed in the booklet supplied with the cartridge, and
may be mentioned in magazine reviews. Here are the recom-
mended values of total capacitance for some popular mag-
netic pickups (MM stands for moving-magnet):
ADC (most MM models) 270 pF
AKG (most MM models) 470 pF
Audio-Technica (most MM models) 270 pF
Empire EDR.9,600LAC,500ID,400TC 150 pF
Empire 200E, 300ME, 20007 270 pF
Goldring (most MM models) 200 pF
NAD 9100, 9200, 9300 270 pF
Ortofon (most MM models) 400 pF
Pickering (most MM models) 270 pF
Shure (V-15/1V, M97 series) 250 pF
Shure (all other MM models) 450 pF
Stanton (most MM models) 270 pF
From this total capacitance value, subtract the capaci-
tance of your turntable’s tonearm wiring and its signal cables,
as well as the value of any capacitors installed in the head-
shell {e.g. the capacitors which are pre-installed on some
Ortofon pickups). To learn the capacitance of your turntable
wiring, check the specifications supplied with the tonearm, or
write to the manufacturer, or as a last resort assume a typical
value of 150 pF.
‘After this subtraction, what remains is the desired value
of preamp input capacitance. Set the Capacitance Selector to
the nearest value. It is not necessary to match the computed
value exactly; with most phono pickups a variation of 50 pF
one way or the other will produce only a very slight change in
frequency response.
Example: Suppose you are using a Stanton 8818S pickup
(270 pF recommended) in a Pioneer turntable (100 pF wir-
ing). 275 minus 100 equals 175 pF, so set the Capacitance
Selector on the preamp to the closest value, 226 pf the
middle position of the switch). Re
If you prefer, you may simply set the Capacitance Selec-
tor by ear while listening to recordings which are strong in
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too low the upper midrange (the soprano voice range) will be
softened and the response at the highest frequencies will be
peaky, leading to edgy violin tone and increased surface
noise. Too high a value of capacitance will bring the upper-
midrange forward while rolling off the extreme highs.
3. MM/MC SELECTOR. This switch sets the input
sensitivity and gain of the phono preamplifier circuit. Set it
according to the output level of your phono cartridge. Move
the switch to MM for cartridges of the moving
magnet, induced magnet, moving flux, and moving iron
(variable reluctance) types, and for “high-output” moving-
coil pickups (i.e., those with a rated output of 1.0 mV or
greater). If your cartridge is a low-output moving-coil pickup
(with a rated output of less than 1.0 mV), move the switch
to MC. :
Here is another way to determine the preferred setting
of the MM/MC switch. Begin by setting it to MM. After you
have completed the installation and wiring of the amplifier,
play a record. You should obtain a satisfyingly loud volume
level with a VOLUME control setting between 9 o'clock
and 3 o'clock. If you have to turn up the VOLUME control
beyond 3 o'clock to get adequately loud sound, turn the
VOLUME back down and re-set the MM/MC switch to MC.
4. PHONO. Plug the signal cables from your turntable
“into these jacks. If 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 for the Right. (On the
1020 preamp the Left-channel input is the jack closer to the
edge of the shelf, and the Right-channel input is the jack
closer to the body of the preamp.) Be sure to insert each plug
fully into the socket, so that the plug's metal skirt fits tightly
over the exterior of the socket. If necessary, carefully crimp
the plug's metal skirt slightly inward, so as to obtain a tight fit
with the socket.
5. TUNER. Piug the signal cables from your radio tuner
into these jacks. If your tuner has both “variable” and “fixed-
level” outputs, it usually is preferable to use the variable
outputs so that you can use the tuner's Output Level control
to match the average loudness of radio programs to that of
records as you switch among input signals.
6. AUX. The “auxiliary” input jacks are for any “line-
level” signal source—such as the playback from a spare tape
deck, the audio line output from a videocassette or videodisc
player, or a television sound tuner.
7. TAPE REC/PLAY. Two types of connectors are pro-
vided for use with a stereo tape recorder: separate pairs of
RECORD and PLAY phono jacks, and a five-pin DIN socket.
if your recorder is equipped only with DIN-type plugs, use
the DIN connector. If your recorder has both a DIN plug and
- pairs of phono jacks, it is preferable to use the phono plug
connections. (Do not use both the phono plugs and the DIN
— plug simultaneously.)
Connect a stereo signal cable from the PLAY jacks to the
recorder's LINE QUTPUT jacks, and a second stereo cable
from the REC jacks to the recorder's LINE INPUT jacks. Use
the color-coding of the cables to ensure consistent connec-
tions of the Left and Right channels at both ends of each
cable. Any kind of stereo tape deck can be used: cassette,
micro-cassette, open-reel, eight-track, or digital.
The TAPE REC/PLAY jacks can also be used to con-
nect a signal processing accessory instead of a tape record-
er. If you have a dynamic-range expander, dynamic noise
filter, impulse noise suppressor ("tick and pop” filter), Dolby
B/C noise-reduction unit, DBX unit, CX disc decoder, or
stereo image enhancer, connect it here. (Connect a stereo
signal cable from the REC jacks to the processor's input
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to the 1020's PLAY jacks.) Then connect your tape deck to
the processor's own tape input/output jacks.
Signal processors which don't depend on the setting of
signal levels or thresholds—such as a graphic equalizer or
the special equalizer supplied for use with some loudspeak-
ers (e.g. Bose, KLH, Electro-Voice) can be connected either
to the TAPE jacks orto the PREAMP OUTPUT jacks. The
choice is a matter of convenience. Usually it is preferable to
connect such devices at the PREAMP OUTPUT in order to
leave the TAPE REC/PLAY jacks free for the connection of
a tape recorder or a level-sensitive signal processor.
8. PRE OUT. These are the normal output jacks from the
NAD 1020 preamplifier. Connect a stereo signal cable from
these jacks to the main input jacks on your power amplifier.
If you have an equalizer, a time-delay ambience-
reproduction unit, or other signal processor which needs
to be installed in the signal path, connect a cable from the
PREAMP OUTPUT jacks to the processor's input, and a
second cable from the processor's output to the main input
jacks of your power amplifier.
The preamp has a low output impedance (600 ohms)
and is capable of driving several amplifiers connected in
parallel, or of driving the long signal cables required to
connect to power amplifiers which are located near the
speakers, or the long cables used to connect “powered”
loudspeakers having built-in power amplifiers.
9. HI-LEVEL PRE OUT. At this special set of preamp
output jacks the signal is 15 dB higher in level than at the
regular PRE OUT jacks, and the output impedance is even
lower: 150 ohms. You may use these jacks if your power
amplifier requires an input level of more than 2 volts to drive
it to full output. The High-Level preamp output jacks may also
be used to drive professional studio equipment; using these
jacks the 1020 is capable of driving load impedances as low
as 600 ohms, and can deliver undistorted signals greater
than 15 volts (+ 26 dBm) to high-impedance loads.
NOTE: the front-panel Phones socket is connected
in parallel with the High Level preamp output jacks; when
low-impedance headphones are plugged into the front panel
they will reduce the signal level and available headroom
at the High Level preamp output jacks.
10. AC LINE CORD. Plug the AC line cord into an AC
wall outlet providing the correct AC voltage printed on the
preamp's rear panel (e.g. 120 volts, 60 Hz in the U.S.). If your
1020 is equipped with a Voltage Selector, set it for the line
voltage provided in your area, before plugging the line cord
into the wall socket.
11. AC CONVENIENCE OUTLETS. (Not in U.K. model.)
The AC line cords of other stereo components may be
plugged into these accessory outlets.
If you have a solid-state power amplifier with a rated
output of up to 150 watts/channel, its AC power cord should
be plugged into the 500W SWITCHED outlet; then the power
amp will be turned on and off together with the preamp, by
the 1020's front-panel POWER switch. The SWITCHED out-
let may also be used to provide power to other electronic
components such as a tuner, equalizer, etc.
Larger power amplifiers, and those with 3-wire power
cords, should be plugged directly into an appropriate
wall outlet.
The UNSWITCHED outlets may be used to supply AC
power to other components, such as a turntable or tape deck,
which should be turned on and off as needed by their own
power switches.
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FHUNI PANEL CONTROLS
1. POWER. Depress this switch to turn on the preamplifier
and any equipment (such as a power amplifier) whose AC
cord is plugged into the SWITCHED convenience outlet on
the rear panel. To switch off the power, depress the button
again and release it.
If you prefer, you may leave the 1020's POWER switch
permanently engaged and use an external switch (such as
a clock timer) to turn the power on and off.
The 1020 is equipped with a turn-on delay which auto-
matically mutes the preamp outputs for several seconds, until
the preamp's circuits are fully stabilized; this prevents the
transmission of loud turn-on transients to the power amplifier.
The same circuit instantly mutes the outputs when the power
is turned off.
2. PHONES. Plug stereo headphones in here. The
circuit will provide proper drive signals for all conventional
stereo headphones regardless of their impedance, with one
exception: electrostatic headphones usually are supplied with
an adapter box which must be connected directly to your
power amplifier's speaker terminals.
Insertion of a phone plug into the PHONES socket auto-
atically mutes the output at the 1020's normal PRE QUT
jacks, thus shutting off the loudspeakers. In order to resume
listening to loudspeakers you must remove the headphone
plug from the PHONES socket.
3. BASS. The Bass control adjusts the relative level of
the low frequencies in the sound. The electrical response of
the amplifier is flattest 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 which sounds most natural to you.
You will note that at moderate rotations the effect of the Bass
control usually is subtle because its action is confined to the
lowest audible frequencies. Only at large rotations away from
center is there a substantial boost or cut at the mid-bass
frequencies which are prevalent in music.
4. TREBLE. The Treble control adjusts the relative level
of the high frequencies in the sound. The electrical response
of the amplifier is flattest 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 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 of details in the sound, but also makes any noise
more prominent. Cutting the treble makes the sound meliower
and suppresses hiss and record surface noise, but too much
Treble cut will make the sound dull.
5. BALANCE. Adjusts the relative levels of the left
and right channels. A detent at the 12 o'clock position marks
the point of equal balance. Rotation to the right (clockwise)
decreases the level of the left channel so that only the right
channel is heard, i.e., shifting the sonic image to the right.
Rotation to the left shifts the sonic image toward the
left speaker.
Ideally the detented center position of the BALANCE
control will be the normal setting. But several common
circumstances may cause unequal balance, requiring a com-
pensatory off-center BALANCE setting to restore the most
uniform spread of stereo sound between the speakers. These
include unequal output from the two channels of the phono
cartridge, differing acoustical environments around the two
speakers, or simply a listening position which 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
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announcer's voice) appearing as a phantom image centered
midway between them.
6. AUXTUNER/PHONO SELECTOR. These three but-
tons, and the adjacent TAPE button, select the signal source
to be heard. When the AUX, TUNER, or PHONG input is
selected, the corresponding input signal is fed to the pre-
amplifier’s circuits and also to the RECORD output jacks
for recording.
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7. TAPE. When this button is disengaged (out), the input
signal chosen by the SELECTOR switch (aux, phono, tuner)
is fed to the controls and to the power amplifier for listening.
When the TAPE button is engaged, the output signal from a
tape recorder (or any signal processor connected to the rear-
panel PLAY jacks) is heard.
The signal to be recorded on tape is chosen exclusively
by the SELECTOR switch, and is not affected by the VOL-
UME or any other control.
When you are making a tape recording, engaging the
TAPE switch enables you to hear the signal as it passes
through the tape machine's electronics and recording-level
controls. However, engaging and disengaging the TAPE
button may slightly alter the signal levels fed out to a tape
recorder; therefore, the button should be kept engaged
during the entire duration of a recording.
With a three-head recorder equipped for off-the-tape
monitoring, the TAPE switch permits you to hear the playback
signal from the tape immediately after the recording is made,
in order to check its quality. In this case use the tape/source
switch on the recorder for switching between the original and
recorded signal.
If you have connected a signal processor such as a
graphic equalizer or dynamic-range expander to the RE-
CORD/PLAY jacks, the TAPE button must be depressed in
order to hear the effects of the processor. Normally the
processor will have its own RECORD/PLAY jacks and tape
monitor switch for use with a tape recorder.
8. MONO. Engaging this button combines the two stereo
channels together to produce monophonic sound, minimiz-
ing vertical rumble and surface noise when listening to old
- monophonic recordings. The button must be OUT for normal
stereo listening.
9. LOUDNESS. Pressing this button engages a
“loudness compensation” circuit which, at low-to-medium
settings of the Volume control, boosts the bass and treble
response of the amplifier. This is to compensate for the
human ear’s reduced sensitivity to low-frequency sounds at
low loudness levels, and for the “masking” of high-frequency
details by environmental noise. The LOUDNESS function
should be disengaged when you are listening to music at
life-like volume levels. And at low levels a more accurate, if
less convenient, loudness compensation may be obtained by
boosting the Bass control.
10. VOLUME. Adjusts the overall loudness of the sound,
in conjunction with the Audio Muting button. The control is
designed for accurate tracking of the two channels, so that
the stereo balance will not shift as the VOLUME contro!
setting is varied.
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PROCESSOR CHAINING
Today's stereo systems often consist not only of the
basic elements (turntable, tuner, tape deck, amplifier and
speakers) but also of assorted signal-processing accessories
which often exceed in number the available places in the
circuit where they can be connected. It then becomes neces-
sary to connect two or more processors in series in a single
processing chain, either in a “tape monitor” loop or between
the preamp and power amp, and it may not be obvious how
the various processors should be chained for best results. ‘
The following sketches outline a suggested order for pro-
cessor chaining, either in a tape-monitor loop or between
preamp and power amp.
PREAMP PREAMP
REC PLAY PREAMP OUT
Impulse Nolse Suppressor Dynamic Range Expander
Equalizer (any type)
+
Stereo Image Enhancer
Dynamic Noise Filter
Y À
CX or DBX Disc Decoder Y
Y A Time-Delay or other
Ambience Reproducer
DOLBY or DBX Noise Reduction
To
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In | } Out Speakers
Tape Recorder
Electronic Crossover
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Power Amp | Power Amp
It is assumed that each processor in the TAPE REC/PLAY
chain has its own set of “TAPE” input/output jacks, to which
the next processor in the chain is connected. Each unit in the
PREAMP OUT chain is assumed to have an “off” or “bypass”
mode which allows signals to pass through without process-
ing when desired.
The outline shown here is not the only practical order-
ing of equipment; you could, for instance, have an equalizer
in the TAPE REC/PLAY loop, at approximately the same posi-
tion in the chain as the dynamic noise filter. And the ordering
of the dynamic expander, equalizer, and stereo image en-
hancer in the PREAMP OUT chain is arbitrary.
The lightning flash with arrowhead, within an equilateral
triangle, is intended to alert the user of the presence of
uninsulated “dangerous voltage" within the product's enclo-
sure; that may be of sufficient magnitude to constitute a
risk of electric shock to persons.
The exclamation point within an equilateral triangle is intended
to alert the user of the presence of important operating and
maintenance (servicing) instructions in the literature
accompanying the appliance.
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