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12.2.4 Playback Equalization Check
Settings
AC mV meter
Test tape
Tape selector . .
Mode
Connect to OUTPUT ter-
minals
STD-341A (333H2,
- 20dB) (6.3kH2, - 20dB)
NORM
Playback
12.2.5 Record/Playback Frequency Response
Adjustment
Settings
AC mV meter
Input signal
Test tape
Tape selector . .
Mode
Connect to OUTPUT ter-
minals
333H2, - 30dBv (31.6mV)
to LINE INPUT terminals
STD-608A (STD-603,
sTD-604)
NORM (CrO2, METAL)
Record
f ,"*"
l3
oom
O O F H m I
3 k H z l e v e l
3 3 3 H 2 e v e l
+ 1 5 .
3 k H z r e v e r
3 3 3 H 2 l e v e l
- 2 5 1
Fig. 12-11 Playback equalization check
Procedure
1. Play the 333H2, - 20dB portion and record the
AC mV meter reading.
2. Then play the 6.3kHz, -2OdB portion, and
check that the meter reading lies within +1.5
t2dB of the reading obtained in step 1 above.
3. Switch the tape selector to METAL, play the
333H2, -20d8 portion again, and record the
meter reading.
4. Then play the 6.3kHz, -20d8 portion again,
and check that the meter reading lies within
-2.5!2dB
of the reading obtained in step 3.
o @
o 0
3 3 3 H 2
- 3 f t 8 v
( 3 1 . 6 m V )
6 . 3 k H z
-30dBv
{ 3 1 . 6 m V )
( T
" u n " . o
)3
B -
lkBz rever -333H2 revel +0 5dB
Fig. 12-12 Record/playback
frequency response adjustment
Procedure
1. Adjust the INPUT level control so that the
meter reads - 27dBv (44.6mV).
2. Record the 333H2, - 30dBv and 6.3kHz,
- 30dBv signals, and adjust VR501 (L ch) and
VR502 (R ch) so that the difference in the
playback output signal level with the 333H2
level as the reference Ievel is +1.0d8 (+0.5-
+2dB).
3. Change the tape selector and DOLBY NR
switch positions (See Fig. I2-i-3), and check
that the frequency response is satisfactory.
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