Nakamichi 581 Owners Manual

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Nakamichi 5 8 1

Discrete Head Cassette Deck
Owner's Manual

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WARNING

TO PREVENT FIRE OR SHOCK
HAZARD, DO NOT EXPOSE
THIS APPLIANCE TO RAIN OR
MOISTURE.

Please record the Model Number
and Serial Number in the space
provided below and retain these
numbers.
Model Number and Serial Number
are located on the rear panel of the
unit.
Model Number: Nakamichi 581
Serial Number :

CONTENTS
Controls and Features -------- 1
Precautions ................ 3
Connections ............... 3
Playback .................. 4
Recording ................. 5
Special Features ............ 7
Recommended Tape ......... 9
Record Calibration and

Bias Adjustment ---------- 11
The Dolby System .......... 13
Maintenance --------------- 14
Troubleshooting ............ 16

Specifications -------------- rear cover

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Egualization is used in record and
playback to achieve optimum signal-to-
noise and headroom performance for
different tape formulations. Like bias, the
proper Eq switch (19) setting must be
selected for each type of tape. Unlike
bias, the Eq switch must be set for both
record fl playback. Normally, you
would set the Eq switch according to the
table, but the excellent high frequency
performance of the Nakamichi 581
permits unusual settings of the Eq switch
for special purposes:

(A) if you wish to make a recording on
SX»type or ZX-type tape for someone
who does not have 70 usec
equalization (sometimes labeled the
"002" or "chrome" position) on his
cassette deck, record with the Tape
switch (20) in the recommended
position but the Eq switch ()9) in
the 120 psec position.

(B) Occasionally. you may encounter
program material with an unusually
high amount of energy at higher
frequencies, (Some synthesizer music
fall into this category) In such
instances you may wish to record on
SX»type or ZX»type tape with the Eq
switch (19) in the 120 usec position
rather than the recommended 70 usec
position. This will result in 374 dB
higher noise, but high~frequency
saturation will be commensurately
reduced. Be sure to make note of the
special equalization on the cassette
label and to play back with the 120
psec equalization,

(C) Some program material may make
large dynamic range demands at
mid~frequencies but with
comparatively little high»frequency
content. In such instances you can
take advantage of the 70 psec
equalization, even with an EX-type

tape, which normally uses 120 usec,

If you record on an EX»type tape
with the 70-usec Eq, you will be
giving up a certain amount oi
high-frequency overload margin but
gaining 3*4 dB of signal-to-noise
ratio. As above, make note of the
special equalization and be sure to
play the cassette With the 70 usec
Eq setting.

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Record Calibration

The various tapes listed on page 9 are
approximately compatible in their
respective categories. It is best,
nevertheless, to choose one specific
formulation for each of the three tape
positions and use these three consistently.
By doing so, you need not worry about
the compatibility of a new and different
kind of tape, and you will gain familiarity
and confidence in recording which cannot
be gained if you are constantly changing
brands. But even the best of tape
manufacturers will often change the
characteristics of their products without
notice. You may, furthermore, want to
experiment With a different brand from
time to time. It is recommended,
therefore, that you periodically check
record calibration and bias.

Record level calibration can be easily
performed on the 581 without the use of
any external test instruments. Proper level
calibration is essential for accurate
tracking of the Dolby noise reduction
cichits. The procedure described in this
section is simple to follow; and once you
gain familiarity with this calibration, it
will take you less than a minute to
perform.

Bias adjustment is usually left to qualified
service personnel. But the 15 kHz test
tone system incorporated in the 581
makes it possible for the user to perform
his own bias re-adjustments. in general,
bias adjustment is required only if your
recordings sound "dull" or bright" in
comparison to the original program
source If you suspect bias
misadjustment, follow the procedure
outlined later in this section.

Record Calibration

(A) Take a few moments to familiarize
yourself with the location and layout
of the "rec cal" screwdriver controls
(23) on the front panel of the 581.

11

:15)

and Bias Adjustment

17...... .i .

Note that there are separate controls
for each of the three tape positions
and for each channel (left and right).

(B) Load the desired cassette and
fast-forward for several seconds
before stopping.

(C) Set the Tape and Eq switches (20.
19) according to the type of tape in
use. See page 9 for recommended
settings.

(D) Set the test tone switch (18) to 400
Hz". This will activate the built-in
400 Hz oscillator, which now
overrides any external input to the
581.

Tone HZ Dollby NR
off in
400"'15K out-'OMpx

®

®

(El Begin recording the 400 Hz test by
pressing the record and play buttons
(7, 11) simultaneously.

(F) The meters are now indicating the
Playback level of the test tone. If
both meters register within one dB of

the "0 dB" mark, there is no need to
perform further calibration.

(G) If the meters do not indicate 0 dB
level, make adjustments to the
appropriate rec cal controls (23)
using the small screwdriver supplied
with the deck. Turn clockwise to
correct a low reading. Turn
counter-clockwise to correct a high
reading.

(H) Return the test tone switch (18) to
the off" position.

Note:

- The 581 is specially designed to
indicate playback levels on the meters
during the recording of the built-in
test tones. During normal recording
from an external source, the meters
will indicate input (record) levels.

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Head and Transport Cleaning

To maintain the Nakamichi 581 superior
performance and to prolong the life of
the heads and pressure rollers, all parts
that come into contact with the tape
should be cleaned frequently and
thoroughly. Dirty heads, capstans or
pressure rollers may result in any of the
followmg symptoms:

-Uneven sound levels.

Loss of high frequencies.

»Wow and flutter.

Damage to cassette tapes.

»Tape squeal caused by excess friction.

Even the best cassettes shed particles

onto the heads, capstans and pressure
rollers. Clean a minimum of once every

ten hours of use, even if you use

premium tapes. If you must use inferior
brands of tape, you may need to clean
after each playing. By observing the
amount of contamination accumulated

on the cleaning stick pad or cotton tip,
you will be able to judge whether you are
cleaning the 581 frequently enough.
Repeated cleanings, if properly done, will
not harm the deck. Hence, it is impossible
to clean too often.

A Cleaning Kit consisting of a plastic
stick, sponge tips, cotton tipped sticks
and a container of alcohol is supplied
with your Nakamichi 58i. When the
alcohol runs out, use commercially
available isoproyl alcohol (preferably
undiluted). "Qtips" and other cotton
swabs may be used in the place of the
sponge tips. Do not, however, rely on
head cleaning cassettes. Some
head-cleaning cassettes are unduly abrasive
and may damage the heads. None of them
clean the capstans and pressure rollers
properly, Perform all cleaning with
alcohol. Use the plastic stick with a
sponge tip screwed onto its end. A
cotton»tipped stick is equally effective,
but be careful not to leave strands of
cotton on any of the cleaned parts.

Clean in the following sequence:

(A) Turn the power switch (15) on. Push
the eject button (2) to open the
cassette lid. Carefully pull the acrylic
cassette compartment cover (1) out
of the cassette lid. Push the cassette
lid back into its well.

(B) With a cleaning stick dipped in
alcohol, clean the surfaces of the
record/playback and erase heads.
Clean with short, firm back-andforth
strokes along the path of tape travel.
Also be sure to clean the tape guide
on the far left.

(C) Press the play button (11). Carefully
apply the cleaning stick to one
pressure roller as it turns. Use light
pressure and an up»and»down stroke
to cover the entire width of the
roller. Repeat with the other pressure
roller. If you are using a
cottonrtipped stick, make sure to
apply the tip to the side of the roller
rotating away from the capstan; the
cotton may otherwise get caught
between the capstan and the roller

Maintenance

(if this should happen, simply press
the stop button and remove the
cotton).

(D) With the transport in the stop mode,
apply a clean section of the cleaning
stick pad to one capstan. Move the
pad up and down the capstan shaft as
it turns. Repeat with the other
capstan.

(El Press the eject button, and carefully
re-insert the acrylic cover.

Cleaning is now completed, but give the
cleaned surfaces a minute or two to dry
off completely before playing a tape.

roller

pressure roller pressure pad lifter

CAUTION:

- Tape guide and heads are critically
aligned at the factory. Do not exert
too much pressure on these parts. it is
better to stroke repeatedly than to
stroke forcefully.

- Do not flood various parts with
cleaning alcohol. After dipping the
stick into alcohol, squeeze off any
excess.

- Be sure to remove any cotton strands
from the cleaned parts.

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