Marantz SD-63 - Optimizing Cassette Recordings; Proper Recording Level Adjustment; Automatic Tape Selector; Tape Selection and Protection

PROPER RECORDING LEVEL
One of the beauties of music is its dynamic range, in other
words, the contrast between very soft and very loud passages.
To capture this contrast on tape the recording levels have to be
set so that the loudest passages do not saturate the tape and
cause distortion. Yet the recording levels should not be set too
low or the soft passages will simply disappear i in the residual
noise.
{f, forexample, you are recording from a record, you should at the
outset find the loudest section of the record. Insert a cassette in
your tape deck and press the REC buttons. You can thus adjust
the recording level without actually recording on the tape.
Start the record again at the beginning and depress the PLAY or
PAUSE button to commence recording. If after setting the
recording levels as explained above the record begins with a soft
musical passage, set the levels to low.
Do not give in to the temptation of changing them. Keep in mind
that the level readings, when placed in the proper perspective
with actual relative loudness levels, fall into the following cat-
egories:
from -10 dB to -5 dB
Approximately +1 dB
Approximately -15 dB
from —10 dB to -5 dB
Broadcast human voice:
Loud music (fortissimo):
Soft music (pianissimo):
Average music level:
CLEANING THE HEADS
The record/play head and erase heads are the most important
parts of the cassette deck. As the tape rubs against the heads
during recording and playback, brown oxide deposits from the
tape accumulate on the heads, guides and pinch rollers. Even
the best cassette tapes will shed some particles of oxide. The
accumulation of this oxide will cause a loss of high-frequency
response, loss of sound volume, intermittent sound dropout and
unsatisfactory results when recording or erasing. Ifthe oxide.is
allowed to build up, it may cause the heads to wear out
prematurely, causing permanent damage.
Open the cassette compartment by pressing the EJECT button.
Clean the heads using a cotton stick as shown in Figure 2.
To clean the tape path, use cotton swabs and methylated spirit
(available at any pharmacy). Please note that ordinary alcohol
should not be used because of its water content.
Dip the cotton swab in the alcohol and clean the tape heads,
capstans, guides and pinch rollers until no more oxide can be .
picked up. If you can see a stripe of brown oxide around the
perimeter of the pinch roller, it is time to clean the entire tape
path. ,
AUTO TAPE SELECTOR
This unit is equipped with.an auto tape selector which automati-
cally sets the bias and.equalizer levels using the detection holes
provided in the cassette shell. The bias and equalizer levels are
automatically set according to the pe of tape as follows. (See
Figure 3) :
EQ; 120 us, Bias; Low
EQ; 70 us, Bias; High
EQ; ate. us, pales Metal
e Normal tapes:
© CrOz tapes:
e Metal tapes:
In some metal tape cassettes, the metal detection holes are not
provided. With these cassettes, the CrO2 tape type indicator
lights up and the recorded sound may be distorted.
MAKING OPTIMUM CASSETTE |
RECORDINGS
TYPE AND BRAND OF TAPES TO USE
In cassette recording, the type and brand of cassette you use has
a great influence on the quality of your recordings. Therefore, it
is worthwhile purchasing the highest-quality cassette available.
Chromium dioxide (CrOz) and metal tapes generally provide
better fidelity than normal, ferric oxide tape.
We recommend the use of cassettes with a recording capacity
of 90 minutes or less. In production, the performance of our
cassette decks is tested using the following tapes.
TDK AC224 (C-60) TDK AD
Special/CrO2 | TDK AC513 (C-60) TDK SA
TDK MA
TDK AC712 (C-60)
TO PROTECT VALUABLE RECORDINGS
In the record mode, information previously recorded on the tape
will automatically be erased. To prevent this from happening,
use.a small screwdriver to break out one or both safety tabs (see
Figure 4 for side A). It is possible to restore the recording
capability of either side of the cassette by covering the opening
with plastic tape (see Figure 5 for side A).
VARIABLE BIAS CONTROL
Usually, this control -can be set to the center click position
because it has been adjusted to provide the optimum bias at that
position. However, strictly speaking, the value of the bias
providing the flattest frequency characteristics varies slightly
depending on the type and brand of the tape. Therefore, to
obtain the maximum performance from each tape used,
Note:
The VARIABLE BIAS control has no effect during playback.
The bias characteristic is generally flat with metal tapes. As a
result, the VARIABLE BIAS control allows adjustment only with
the NORMAL or CrOz position, and the bias is constant with the
METAL position regardless of the control knob position.