Harman Kardon CD 401 - Bias Fine Trim Feature; Record Calibration Feature

Bias Fine Trim Feature Record Calibration Feature
The optimal recording bias rating of the tape of each brand
is somewhat different from that of other brands. The bias
fine trim feature is provided to enable fine adjustment for
such difference.
The high frequency range tends to be attenuated if the bias
current is higher than the rated value for a tape while it
tends to be boosted if the bias current is less than the rated
value.
This unit aims to obtain a flat frequency characteristic by
recording 400 Hz standard signal in the left channel and
12.5 kHz standard signal in the right channel, and by ad¬
justing the BIAS FINE TRIM knob so that both channels
show the same playback level.
Operate as follows:
1. Insert a cassette tape in the CASSETTE COMPART¬
MENT and place the BIAS and EQUALIZATION
selectors at the position corresponding to the using
tape type.
2. Press the TAPE MONITOR switch in the MONITOR
position.
3. Press the RECORD
and PLAY buttons
together to start the
tape. With these two
buttons pressed, tape
recording starts.
Each tape has different
sensitivity. As a result, the
playback level may be
deviated from the LED
LEVEL DISPLAY reading.
The record calibration
feature adjusts the LED
LEVEL DISPLAY reading to the specified value for each
tape so as to enable proper recording and playback level
setting. This is especially important for recording with the
Dolby NR system.
Operate as follows:
1. Insert a cassette tape of the type which is most fre¬
quently used into the CASSETTE COMPARTMENT.
2. Press the BIAS and EQUALIZATION selectors ac¬
cording to the tape type.
3. Press the TAPE MONITOR switch in the MONITOR
position.
4. Press the RECORD and PLAY button together to start
the tape, and keep pressing the RECORD CALBRA-
TION TONE button.
5. If the LED LEVEL DISPLAY shows 0 dB, no adjust¬
ment is required.
6. If the indicated level is above or below 0 dB, adjust the
RECORD CALIBRATION controls.
If the level indication is lower than 0 dB
4. Keep the BIAS TONE button pressed. 400 Hz signal
and 12.5 kHz signal are recorded in the left and right
channels, respectively.
5. Compare LED LEVEL DISPLAY left and right channel
readings. Turn the BIAS FINE TRIM knob if right
channel reading differs from left channel reading so
that right channel reading equals to left channel read¬
ing.
Turn the controls clock¬
wise with a thin screw¬
driver.
When the right channel level is higher
OdB
m i ! m i i ..
Left channel
(400 Hz recording)
OdB
f.:xx:r.:r.i " i .r ziz.... i
Right channel
(12.5 kHz recording)
Turn the knob counterclockwise
If the level indication is higher than 0 dB
OdB
SHHUSHm
OdB
_i—L_i .
record cal
Turn the controls coun¬
terclockwise with a thin
screw'd river.
When the right channel level is lower
OdB
Em i mu i ..i-i-L-i
OdB
I n"TT ill; EX I
Left channel
(400 Hz recording}
Right channel
(12.5 kHz recording)
boost
Turn the knob clockwise
Note: Adjustment to 0 dB may be failed if the used tape
is old or a poor in quality.
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