NAD 6215 User guide

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REAR PANEL CONNECTIONS
1. LINE IN. The NAD 6125 is intended to be connected
to Ihe Tape REC and PLAY (output and input) jacks
at the rear
of any conventional stereo amplifier. Insert the phono plugs at
one end of a stereo connecting cable fully into the LINE
IN
sockets on the 6t25 . At the other end of the cable, insert the
plugs into the TAPE OUT or RECord jacks of the amplifier.
Use the color coding of the plugs to identify the channels;
for instance, if one of the plugs
at each end of the cable is red,
connect the red plug to the R (right channel) socket of both the
amplifier and the NAD 6125.
2.
LINE OUT. To play tapes, plug one end of a stereo
connecting cable into the NAD 6125's LINE OUT jacks, and
plug the other end into the TAPE IN, PLAY, or MONitor input
jacks of the amplifier. Make sure that each plug is inserted
fully into its socket, and observe the color coding of the plugs
to ensure that the stereo channels are connected consistently.
3. AC POWER CORD. Connect the AC power cord
to a
convenient wall outlet or to an "unswitched" AC convenience
outlet at the rear of your amplifier.
A note on fnstallatlon. The excellent performance of
the NAD
6125 stereo tape recorder depends on an array of
precisely machined parts, fine bearings, smoothly polished
surfaces, sensitive detection of the weak magnetic fields in
tape recordings, and amplification of very small signal volt-
ages. Consequently the recorder's performance can be
adversely aHected by external magnetic fields, electrical in-
terference, vibration, heat , mOisture, or chemical fumes .
Thus if it is placed directly on top of a power amplifier, the
6125 may pick up a low-frequency hum from the amplifier's
power transformer.
If you wish to install it next to an amplifier
on the same shelf, place the 6125 on the le ft so that its cas-
sette compartment will be located away from the amplifier.
The 6125 should not be placed on a loudspeaker or on a
television set (a source of strong magnetic fields as well as
vibration), nor in direct sunlight, nor very close to a steam
radiator, nor in a workshop where metal filings and chemicals
are found. The 6125 will function best at temperatures that are
comfortable for people, and it can be stacked or shelved with
the remaining components in your stereo system.
If you are located near a powerful television or radio
transmitter (including a citizen's band or short-wave unit) you
may pick up interference, especially when playing previously
recorded tapes. If you encounter this type of radio-frequency
interference, you may succeed in reducing it by experimenting
with the location and orientation of the recorder. Ifthe problem
perSists, your dealer or a service shop may be able to add
approved circuit modifications or extra internal shielding.
Connecting two recorders. Some stereo amplifiers have
two sets of tape inpuVoutput jacks, with front-panel switching
~
e lightning flash with arrowhead , wi thin an eqUilateral
lriangle, is intended to alerl the user of the presence of
uninsulated " dangerous voltage" within the product's enclo·
sure ; that may be at sufficient magnitude to constitute a
risk of electric shock to persons .
3
to permit using either of two tape decks for recording or
playback and to permit copying tapes from one to the other.
If your amplifier has only one set of connections for a tape
recorder, it
is still possible to use two recorders with it. The
most convenient and flexible method is to purchase an exter-
nal sWitch-box (Tandy Radio Shack #42-2105 or equivalent),
which will provide inpuVoutput connections for up to three
recorders and allow copying among them. The alternative
methods described below are less flexible, but they cost
less and yield equally good recordings.
Copying. Connect the "copying" recorder (the machine
on which the new copy will be recorded) to the amplifier's
TAPE recording/playback jacks as described above. Then
connect to the amplifier's AUXiliary input a cable from the Line
Output jacks of the "source" recorder (the machine containing
the tape that you want to copy), and switch the amplifier's
Input Selector to AUX.
If an AUX input is not available, an alternative procedure
is to disconnect the cable from the amplifier's tape RECord-
ing output, and connect the "source" recorder's Line Output
directly to the copying recorder's Line Input. With this con-
nection you must activate the copying recorder's RECORD
function in order to monitor the playback output of the
source machine.
Parallel recording . Two recorde rs can be wired in par-
allel to permit simultaneous recording on both. Obtain two "
V-
connector" adapters, each having two female phono sockets
and one male phono plug
(e .g., Tandy Radio Shack #42-2436
or equivalent). Plug one V-connector in lo the Right channel
Tape RECording jack of the amplifier, and connect the Right
channel (red) plugs of two stereo cables to the V-connector's
two sockets. Plug the other V-connector into the Left channel
Tape REC jack, and connect the left-channel plugs (usually
black) of the two stereo cables
to the V-connector's sockets.
Finally, at the opposite end of the two stereo cables, connect
to the Line Input jacks of the two recorders.
This hookup allows you to record freely on either ma-
chine, or simultaneously on both, but not to copy tapes from
one to the other.
NOTE: This method of parallel connection works well for
recording, but
not for playback. If you use V-connectors to
combine the Line Output signals from two tape decks, each
machine's output will tend to short-circuit the other's, yielding
a low playback level and possibly higher distortion. Only one
tape deck's Line Output signals can be fed
to the amplifier's
Tape PLAY input jacks.
To hear the playback from the second recorder, connect
its Line Output to the amplifier's AUX input. But observe this
precaution: never switch the amplifier's Input Selector to AUX
while recording on the machine whose output is connected to
AUX; doing so would create a feedback oscillation that could
damage your loudspeakers.
~
e exdamation point wi thin an equilateral triangle is i ntended
to alert the user of the presence of important operating and
maintenance (servicing) instructions in the literature
accompanying the appliance .

FRONT PANEL CONTROLS
1. POWER. Press this switch to turn on the power to the
cassette deck. Press again and release to turn the power off,
A green LED at the left end of the recording level display
is illuminated when the power is on.
The capstan drive motor runs continuously when the
power is on. To prolong the life of the motor, switch the power
on only when the recorder
is being used, and switch it off
when you are listening to broadcasts or disc records.
2. EJECT. When this button is pressed, the door of the
cassette compartment swings open to allow a tape to be
inserted
or removed, The tape cassette is held in a carrier
within the door assembly.
To insert a tape cassette, remove it from its protective
box. Hold it so that its thick edge faces down, and so that the
full tape spool is at the left side of the cassette. Press the
EJECT button to open the door, slide the cassette into the
door's carrier slot, and push the door to close it.
NOTE: Always press STOP to disengage the tape trans·
port mechanism before pressing EJECT to open the door. (If
the machine is in the PLAY or RECORD mode the EJECT
button
is automatically disabled for safety,)
3, TURNS COUNTER. Th is counter registers the turns of
the take·up spool in the cassette. Press the adjacent button
to
re-set the counter to 000 at the beginning of a tape; then the
counter readings will provide a convenient method of identify·
ing the locations of selections on the tape. It will accumulate
a maximum count of approximately 450 over the length of a
C·60 tape, about 700 for a C·90, and about gOO for a C·120.
4. FAST FORWARD/CUE. This button winds the tape
rapidly forward from the left to the right, I.e" from the
beginning toward the end of a recording,
If the tape transport is in the STOP mode. disengaged
from the tape, then the button will latch down when pressed;
the tape will continue to fast·wi
nd forward until you press
STOP or until the end of the tape is reached, At the end of the
tape the transport automatically disengages. returning to the
STOP mode after a brief delay, Since the record/playback
head
is not in contact with the tape, no sound, is heard.
If the tape transport is in the PLAY (or PAUSE) mode,
pressing the FAST FORWARD button activates the CUE
function, The tape winds forward only as long as you continue
to press fhe FAST FORWARD button in. The transporl
reo
mains engaged. automatically resuming PLAY (or PAUSE)
when you release the button. The heads remain in contact
with the tape,
so any recorded material on the tape will be
heard as a loud, high'pitched squeal; this allows you easily to
find where recorded selections beg
in and end, TURN DOWN
YOUR AMPLIFIER VOLUME CONTROL to prevent damage
to your speakers when using this cue mode,
5. REWIND/REVIEW. This button winds the tape rapidly
from the right (the take·up spool) toward the left (onto the
supply spool),
If the tape transport is
in the STOP mode, disengaged
from the tape, then the REWIND button will latch down when
pressed; the tape will continue to rewind rapidly until you
press STOP
or until the beginning of the tape is reached,
Since the head is not in contact with the tape, no sound will
be heard,
If the tape transport is in the PLAY (or PAUSE) mode,
pressing the REWIND button activates the REVIEW function.
The tape winds rapidly back only as long as you continue to
press the REWIND button in. The transport remains engaged,
automatically resuming PLAY (or PAUSE) when you release
the button, The heads remain in contact with the tape while it
winds, so any recorded material on the tape will be heard as a
loud, high-pitched squeal; this allows you easily to find where
4
recorded selections begin and end, TURN DOWN YOUR
AMPLIFIER VOLUME CONTROL
to prevent damage to your
speakers when using this cue mode .
6. PLAY. When this button is pressed, the tape is moved
from left to right at normal playing speed, the recorder's heads
are brought into contact with the tape, and the playback
circuits are activated, At the end of the tape, the transport
automatically stops and disengages itself from the tape,
7,
STOP. This button stops the tape motion and disen-
gages all of the taoe transport functions (except PAUSE). If
the machine was in PLAY or RECORD, pressing STOP causes
the heads to retract from the tape, allowing the door to be
opened by the EJECT button,
8. RECORD. Pressing this button activates the recording
circuits and also engages the transport to move the tape over
the heads so that a recording can be made. The red REC light
in the recording level display illuminates to indicate that the
NAD 6125 is in the recording mode. When recording, the
machine automatically erases any previous recording that may
be on the tape.
NOTE: In many tape recorders the REC button only
switches on the recording circuits , and it is necessary to press
both REC and PLAY to engage the tape and make a record-
ing, But in the 6125 the single REC button commands the
entire recording process. One-button recording is convenient ,
but it means that if you accidently press REC instead of PLAY
when you want to play back a tape, the machine will imme-
diately go into the recording mode and begin to erase the
recording that you wanted to hear,
To prevent such acci·
dents, remove the erasure·prevention tabs (as described
later) from any recorded cassettes that you don't intend
to re·record on. With these tabs removed, the REC button
cannot be depressed.
To stop recording and de·activate the recording circuits,
press
STOP.
To stop recording briefly while leaving the recording
circuits activated, press PAUSE; then press and release
PAUSE again when you are ready
to resume recording,
g, PAUSE. Pressing this button once retracts the rubber
pinch roller from the capstan, thus halting the motion of the
tape
in the PLAY and RECORD modes, while leaving the
playback or recording circuits active,
Pressing and releasing the PAUSE button a second time
provides
an instant resumption of tape motion for playback or
recording.
NOTE: The PAUSE control is intended to stop the tape
motion temporarily,
To stop the tape for more than a few
minutes, use the STOP button,
The PAUSE function can only be disengaged by pressing
and releasing the PAUSE button; unlike the other functions of
the tape transport, PAUSE does not automatically disengage
when STOP is pressed, If you forget that you have left the
PAUSE mode engaged, the Model 6125 may appear to be
malfunctioning when you try to record or play tapes, When
you press RECORD, for example, the red RECORD light w
ill
illuminate and the incoming signal will register on the record-
ing level display, but no signal will be recorded on the tape
until the PAUSE is released. (Then the changing number in
the TURNS COUNTER will provide confirmation that the
tape
is moving .)
10 . MPX FILTER. This filter is intended for use when
you are making recordings with Dolby B noise reduction,
Any ultrasonic interference
in the input signal during record·
ing, such as a multiplex pilot signal in an FM tuner, may cause
mistracking of the Dolby circuit and yield dull sound when t
he
recording is played back, To prevent this mistracking and
preserve a flat frequency response with Dolby
NR , the MPX
filter should be switched ON (by pressing the button in) when-

ever a recording is made using Dolby B. The filler blocks fre·
quencies higher Ihan abcut t5 kHz in the signal.
When playing previously recorded tapes, a very slight
extension of high·frequency bandwidlh may
be obtained by
switching the MPX filter OFF (button out). But remember to
switch back in when making recordings with Dolby B.
If you make any recordings with the Dolby NR switched
OFF, the MPX filter is optional. It is also optional when you are
using Dolby C NR, since the Dolby C circuit contains some
ultrasonic filtering of its own .
11. DOLBY NR. The recorder is equipped with two types
of Dolby noise reduction. Dolby C provides the greatest
quieting of tape hiss, important when taping "live" musical
performances
or wide·range recordings (digilal records, for
example). Dolby B provides optimum compatibility with older
tape recorders, portable and automobile stereo lape players,
and should also be used when playing most pre·recorded
music cassettes .
Each type of NR involves complementary processes
that are intended to match each other
in both recording and
playback. Thus if a tape is recorded with Dolby C noise
reduction, it must also be played back with the Dolby C circuit
operating
in order for the benefits of the Dolby system to be
obtained. Similarly, if Dolby B
is used in recording it should
be used in playback
as well. To avoid confusion, it is recom·
mended that you label each cassette "B" or " c" when it is
recorded, to indicate the type of noise reduction used.
Both types of Dolby NR operate by selectively compress·
ing the dynamic range of the middle and high frequencies in
the signal during recording. I.e. the circuit selectively boosts
the level of those middle·to·high frequency sounds that occur
at a naturally low level, so that these sounds are recorded on
the tape at a level substantially higher than the tape's own
hiss. Then,
in playback, these signals are expanded back to
their original dynamic range; the quiet middle and high fre-
quency sounds that were boosted are finalty cut back down
to their original levels, and the tape's hiss is reduced
at the
same time .
Dolby Band C differ in the amount of complementary
boostlcut that they provide, and in its frequency distribution.
Dolby B operates mainly at high frequencies and suppresses
tape hiss by a maximum of
10 dB. Dolby C operates at both
middle and high frequencies and reduces hiss by as much as
20 dB. The two Dolby systems are
not interchangeabl~. If you
record with Dolby B and play back with Dolby C (or vice versa)
the tonal balance of Ihe musical sound will be substantially
altered.
Also, any brightening or dulling of the sound that
is
caused by a mismatch between the recorder and the tape will
produce mistracking in Ihe Dolby circuit and yield an exag·
gerated brightening or dulling of Ihe playback sound. So when
Ihe Dolby circuits are to be used, it is especially importanllhat
the TAPE SELECTOR be correctly set to match Ihe tape (both
:in recording and in playback).
12. TAPE SELECTOR. This switch selects the correcl
bias (for recording) and equalization (for playback), for each of
three standard types of cassette lape. Whenever you record
or playa tape, this switch musl be set to match the tape. If you
are not careful aboul this, the clarity and lanai balance of your
recordings will vary a great deal, especially when Dolby noise
reduction is used.
f. Normal. The largest variety of casselIe lapes are
intended for use wilh Ihe NORMAL setting
of the TAPE
SELECTOR. Look
al the cassette package for a statement of
"normal bias" or "120 fLsec " equalization. In general, tapes
described as "ferric oxide," "low noise," or having the Roman
numeral f in their deSignation, are intended for the NORMAL
selting.
5
It. Cr02' The cr02setting is intended for tapes employing
chromium dioxide or the "chrome·equivalenl" cobalt·doped
high·bias ferric oxide. Usually these are identified as requiri
ng
"high bias," "70 fLsec " equalization, or have Ihe Roman
numeral
II in their designation.
fV. Metal. The Metal selling should be used with metal·
particle tapes, which may be labeled with Ihe Roman nu·
merallV.
While the TAPE SELECTOR switch provides Ihe large
changes
in recording bias and playback equalization that are
needed to accommodate the Ihree standard classes of tape,
there are significant brand-la-brand differences in sensitivity
and frequency response among tapes within each group.
If you wish, you can use the 6125 10 make recordings on
any brand and type of tape, using any setting of Ihe TAPE
SELECTOR, withoul harming either the recorder
or the tapes.
And by experimenting with vanous tapes you may exploit their
different tonal qualities to produce pleasing
results-using the
recorder , in effect, as a tone control.
But the basic purpose of a high·fidelity tape recorder is to
provide
an exact replica of the original sound, capturing and
preserving it for later playback. This is what the NAD
6125
is designed to do. If you want to make the most accurate
recordings, you must use tapes similar to those used
in the
factory for calibrating the recorder's circuits. This
is especially
important when Dolby noise reduction
is used, because any
departure from accurate high·frequency response in a record·
ing (due to a mismatch between recorder and tape) will cause
decoding errors in the Dolby circuit during
playback-and this,
in turn, will cause larger errors in frequency response , making
the sound excessively bright or dull.
For information on tapes that are compatible with the NAD
6125, see your NAD dealer.
13. RECORDfNG LEVEL. This knob controls the strength
of the audio signal fed to the tape when a recording
is being
made. The signal strength is shown on the recording level
display, above.
The RECORD LEVEL control
is actualty two co·axial
controls (one for each stereo channel), friction·coupled so that
they normally rotate together.
It is possible to alter the stereo
balance by adjusting the two controls differently. The left chan·
nel is controlled by the central part of the knob, while the right
channel
is controlled by the outer part (the sleeve around the
circumference of the knob).
14. RECORDING LEVEL
Of SPLAY. This dual row of
LEOs displays the peak level of the signal in each channel
during recording
or playback. The LEOs ranging from -20 dB
to 0 dB are green and indicate normal recording levels. The
+2, +4, and +6 dB LEOs are red and indicate the maximum
permissible levels.
In general, you should adjust the recording level so that
the loudest portions of the music are recorded at levels be·
tween - 4 and +2 on the display. With music that spans a
large range of volume levels, such
as a symphony, this may
mean that the quiet portions of the music will be recorded at
indicated levels of -20 dB or even lower (with no LEOs
illuminated); this is normal.
To learn how to sel optimum recording levels, the follow·
ing experiment is recommended. Select a typical recording of
music and record an excerpt from it several times in succes-
Sion , setting the recording level progressively higher each
time. For example set the maximum peak level
at about
- 10 dB the first time, and repeat it at about - 4, at 0, at + 4,
and finally at over +6 dB. Then play back the recordings and
lislen for symptoms of tape saturation
in the sound. (Adjust
your amplifier's volume control
to compensate for the different
loudness levels of the sample recordings, so that you can
focus your attention on the quality of the sound without being

distracted by volume differences.)
At a peak level of -
10 dB the sound should be clear,
open, and detailed, but the background of tape hiss may be
bothersome. At peak levels of +4 or +6 dB you probably will
begin to hear the effects of tape saturation: boomier bass,
mushy midrange, or dull treble. Also, tape saturation will
reduce the peak levels: a signal that was recorded at
+4 dB may pl ay back at only 0 or +2 dB.
The optimum recording level
is the highest level that you
can use
(In order to minimize audible hiss in playback), but
wIthout encountering audible symptoms of tape saturation. As
a general rule, you can use higher recording levels for brief
transient sounds (such as drumbeats) than for continuous,
sustained tones (e.g
., the singing voice). And you can use
higher recording levels for sounds whose energy
is concen-
trated at midrange frequencies (e.g., spoken voice) than for
sounds having a great deal of energy at
very high frequencies
(cymbals, bells, harpsichord) or at very low frequencies (pipe
organ, bass drum). With the latter, the peak level usually
should be set no higher than about -2 dB.
When in doubt it usually is best to err on the conservative
side, sacrificing a bit of potential signal-to-noise ratio in favor
of a little extra undistorted headroom for musical peaks. With
Dolby C noise reduction to minimize any audible tape hiss,
you can afford to under-record slightly; and this practice will
help to ensure that you preserve all of the air, brilliance, and
detail in the original sound.
You may find that, in order to achieve peak recording
levels near 0 dB, you have to set the RECORD LEVEL control
to a different position for recording FM broadcasts than when
recording from phonograph records. This
is normal.
15 , MIC. The microphone socket will accept a signal from
any conventional microphone whose cable terminates in a %"
(6mm) phone plug. If your microphone terminates in another
type
of connector, plug adapters can be used to convert to
the standard phone plug. Any type of microphone, with any
Impedance , may be used; but a low or medium impedance
mike is recommended .
The microphone signal is recorded equally in both chan-
nels, as a monophonic signal
in the center of the stereo slage.
If you wish to make stereo recordings with two (or more)
microphones, connect the mikes to a microphone preamp!
mixer and then connect the output of the mixerto the
LINE
IN jacks.
When a microphone plug is inserted into the MIC socket,
the input signal from the LINE
IN jacks is automatically dis-
connected. (If a loud signal is present at the LINE IN jacks, a
faint trace
of it may still leak into the microphone input. So if
you are making a critical recording with a microphone, the
Signal cables should be disconnected from the LINE IN jacks
when the mike
is used.
In order to resume recording from a tuner or amplifier via
the LINE inputs, the microphone plug must be removed from
the MIC socket.
When recording a spoken voice, the most natural voice
quality will usually be obtained by placing the microphone at
a distance of
15 to 30 cm (6 to 12 inches) from the mouth.
Holding the mike
very close to the mouth, in the manner of
rock singers, will produce poor sound with many microphones.
CAUTION: When the Model 6125 is in the RECORD
mode, the signal being recorded also appears at the LINE
OUT jacks and so is fed to your amplifier for monitoring. If
you record with a microphone in the same room, its signal will
then be amplified and reproduced by your loudspeakers. The
resulting "feedback" howl could damage the speakers.
To
prevent this possibility, whenever you record with a micro-
phone you should turn off your amplifier or switch it so that
the tape recorder'S output cannot be amplified.
6
OPERATING PROCEDURES AND HI NT S
To Play Recorded Tapes
1. Before inserting a cassette, check it to be sure that the
tape is straight and taut where it is exposed at the thick edge
of the cassette. If necessary, insert a pencil into either tape
spool and manually wind the tape until any slack
is taken up .
2. Press the EJECT button to open the door. Insert the
cassette with the thick edge down and with the
fu ll spool of
tape at the left side. Push the door closed.
3. If the tape has been in storage for several months, it
may be necessary
to loosen the tape pack by fast-winding the
tape. (Press FAST FORWARD
to wind the tape through its
entire length, then REWIND to return to the beginning.) If the
tape sticks and will not fast-wind, hold the cassette in the palm
of your hand and slap it face-down on a tabletop.
CAUTION: Str ike only the flal face of the cassette against
the table. If you strike the edge of the cassette against a hard
surface, you could break it.
4. Set the TAPE SELECTOR to match the type of tape
being played. For pre-recorded music cassettes this
is usually
NORMAL. In the case of chromium dioxide tapes, examine the
package:
if " 120 microsecond" equalization is specified, use
NORMAL; if not, set the switch to Cr02'
5. Set the Dolby NR switch to match the noise-reduction
system that was used to record the tape.
If the tape was
recorded on the NAD 6125 using Dolby C (or on another tape
deck equipped with Dolby
C) , set the Dolby NR switch to C for
playback. If the tape was recorded on a machine equipped
only with Dolby B, or is a commercially pre-recorded music
cassette made with Dolby B encoding, set the Dolby
NR
switch to B.
If the tape was recorded with no nOise-reduction, switch
the Dolby
OFF. Also, some older pre-recorded music cas-
settes made with Dolby B may have been so poorly processed
that they sound dull with normal Dolby B playback decoding.
In such cases you may obtain better sound by switching the
Dolby OFF during playback and then using your amplifier's
tone controls to obtain the most realistic tonal balance.
If the tape was recorded with DBX noise reduction, switch
the Dolby OFF and connect the tape deck to an external
DBX
If noise-reduction decoder for playback.
Remember to switch the Dolby NR back to B or C when
recording your own tapes.
6. Switch OFF the MPX filter (button out) to obtain the
most extended high-frequency response during playback. (But
remember to switch the filter back
on when making recordings
with Dolby B.)
7. Press PLAY.
To Make a Recording
1. Before inserting a cassette, check it to be sure that the
tape
is straight and taut where it is exposed at the thick edge
of the cassette. If it is not, manually wind the tape to take up
the slack.
2. Press the EJECT button to open the door. Insert a
blank cassette with the thick edge down and with side 1 (or
A)
faCing you. Through the window in the cassette you should
see a full spool of tape on the left side.
3. If the tape is new and has just been unwrapped for the
fi rst time, the tape pack may have developed some friction
during the period of storage since
it left the factory. To loosen
the tape pack, press FAST FORWARD to wind the tape
through its entire length,then press REWIND to return to
the beginning.
4. Set the turns counter to 000. Then, as you make the
recording, you can take note of the counter reading corre-
sponding to each recorded selection.

i I
5. Set the TAPE SELECTOR switch to match Ihe lape thai
you are using.
6. Sel the Dolby
NR switch 10 C (for maximum quieting of
background tape hiss), unless you are recording a tape for
playback on a portab
le or other machine that has only Dolby
B or no noise reduction at all. When recording with Dolby B,
switch Ihe MPX filter ON (button in).
Z In order 10 determine the optimum recording setting of
the RECORD LEVEL control, it is desirable to activate the
recording circuils without actually depositing a recording on
the tape. To do this, press PAUSE and then REC. Observe the
recording level display while setting the RECORD LEVEL
control so Ihat the highest levels in Ihe music regisler are at
approximately 0 dB.
When you are ready to proceed with the recording, press
and release the PAUSE button to start the tape moving. (Its
motion will be confirmed by the gradual ly changing reading of
Ihe turns counter.) Since Ihe recordi ng circuits have already
been aclivated, Ihere
is no need to press REC again.
8.
In most cassettes the first few inches of tape al either
end is a "leader" with no magnetic coating. Remember
to let
the tape advance by several counts (on the turns counter)
before beginning the recording.
9.
To interrupt the recording al any point, press PAUSE;
this will stop the lape while leaving the recording circuits and
recording level display active.
To resume recording, press and
release PAUSE again.
10 . At the end of the recordi ng session, press STOP.
If you want 10 continue recording on the other side of the
cassette, press FAST FORWARD to advance the tape
to the
end of side A; remove the cassette , turn it over, and insert it
with side B facing you. Press REC to resume recording.
To Erase Tapes. The recorder automatically erases pre-
vious recordings as a fresh recording is made . To erase an
entire tape, simply turn down the RECORD LEVEL control
to minimum, press REC, and record over the full length
of the tape.
Prevention of Accldentaf Erasure. Every cassette is
equipped with two plastic tabs in cutaway holes in the top
(thin) edge of the cassette. One tape is for side A and the
other for side B; when you hold the casselle so that side
A faces you, its tab
is on the top of the cassette near the
left end.
These tabs engage a safety interlock in the recorder that
permits Ihe recording and erasing circuits to be activated. If
you think that you may wish to erase and re-use a cassette in
the future, do not disturb the tabs. But if you have made a
valuable recording that you want
to keep, you can safeguard
it against any possibility of accidental over-recording and
erasure by breaking off the corresponding tab. (If the valued
recording occupies both sides of the cassette, break off
both tabs.)
If you change your mind and decide to re-record over
the tape after having removed Ihe erasure-prevenlion tabs,
simply cover the cutout wilh a piece of cellophane or olher
adhesive tape.
Maintenance. The bearings and olher moving parts
in
this recorder are assembled with long-life lubricants and
requ ir e no periodic maintenance. But in order to preserve the
NAD 6125 's high level of performance, all surfaces thai the
tape comes in contacl with must be maintained free of dirt
and free of magnetism.
7
Regular cleaning is the primary requirement. Dirt particles
smaller than a Iwo-Ihousandlh of an inch (0 . 01 mm), if lodged
on the polished surface of Ihe record/play head, can cause a
large falloff
in high-frequency response. One easy way 10
clean the heads on a daily basis is to use a head-cleaning
cassette (a cassette that contains a lextured paper tape
inslead of magnelic lape
). Play the cleaning casselle for
several seconds before each recording or playback session,
and as Ihe cleaning tape rubs over the heads it will remove
accumulated parlicles of dust and tape oxide.
At longer
intervals-weekly or month ly depending on how
heavily you use the
machine-a liquid solvent or spray should
be used to remove lape oxides
or sticky residue deposited on
Ihe heads, capstan, and pinch roller. Tape head cleaning
sprays and fluids are available from your hi-fi dealer and from
other sources .We recommend a solution whose active ingre-
dient is either alcohol (denatured or "isopropyl") or Freon (a
fluorinated hydrocarbon compound); some head cleaners con-
tain both. If you use isopropyl alcohol, check to be sure that
the solution does not contain any unwanted oily substances
such as Lanolin.
To clean the tape transport, remove any casselle from
the machine. Use the fluid or spray
to moisten a cotton swab,
then use the moist swab to scrub the black erase head, the
silver-colored record/play head, the steel capstan, and the
black rubber pinch roller.
The door of the cassette compartment can be removed to
provide easier access to the heads for cleaning and demag-
netizing. The door is actually in two parts: the framework that
holds the cassette, and an extenor plastiC trim panel contain-
ing the NAD logo and the transparent window. Press EJECT to
swing the door open; remove any casselle, and press firmly
upward
on the exterior surface of the door to detach it from the
cassette holder. (Your NAD dealer can show you how to do
this
.) To re-install the door panel, align its fastening clips with
the retainers on the casselle holder, and slide the panel down
into place.
During months of regular use the heads and sleel capslan
may acquire a magnelic charge that will add hiss to all lapes
played or recorded in the machine. Approximately once a
year Ih
is charge should be removed by us i ng a head
de -magnetizer.
Before using the de-magnetizer, switch off the power to
the recorder. Open the cassette compartment,
and remove its
door panel. Take away any cassettes from the vicinity. Hold
the de-magnetizer away from the machine (to protect the
recorder from the de-magnetizer's turn-on surge); plug in the
de-magnetizer, turn
it on, and then slowly pass it s probe tip
over the heads and capstan. (The probe tip may
be allowed to
touch the heads and capstan-but only if its metal surface is
covered with a plastiC sleeve or wrapped with plastic tape to
prevent
it from scratching the heads.) Move the probe tip
slowly out of the casselle compartment, and move the de-
magnetizer at least a meter (3 feet) away from the recorder
before switching it off. If you aCCidentally switch off the
de-magnetizer while its probe tip
is within the cassette
compartment, the entire de-magnetizing procedure must
be repeated.
If you prefer not to do it yourself, you may have a
complete annual cleaning and de-magnetizing service done
for your recorder by your NAD dealer or by
an independent
service shop. At the same time, you may have the recorder's
internal bias and Dolby circuit adjustments calibrated to match
the particular brand and type of tape that you prefer to use.

ELECTRONICS
LONDON/BOSTON