Teac A-450 - VU METER CALIBRATION -PLAYBACK-; FREQUENCY RESPONSE -PLAYBACK-; SIGNAL TO NOISE RATIO -PLAYBACK-

7-1-3. VU METER CALIBRATION —PLAYBACK—
7.
8.
Adjust VR107/207 for +3 VU (D0) on the VU meter.
Set the DOLBY NR switch to the IN position and
make sure the VU meter indication is the same, also.
7-1-4. FREQUENCY RESPONSE —PLAYBACK—
NOTE
In the following procedure, adjust VR101/201 so
that the measured values on all setting of the EQ
switch are within the specified response limits.
Hi-Fi TAPE
9.
Load a TEAC MTT-116U test tape and play its test
signals from 40 Hz up to 14 kHz.
10. Adjust VR101/201 so that the readings of the higher
frequency signals on the VTVM are within the response
limits.
CrO, & Fe-Cr TAPES
11. Repeat the above procedure, with the following ex-
ceptions.
Test tape: MTT-116K
EQ switch: Both “1 & 2” positions
RESPONSE IN dB
ea + +
bon FO NM fb
ai ee , TTT Pee EES PL oa
: |.TEST TAPE: MTT-116U (EQ 3)
TTT | MTT-116K (EQ 1, 2)
+t 4+ o oe
+2 +2 Li |
$titt |
=E a
ca
+ Ht tt +
FREQUENCY IN Hz
Fig. 7-5 siceeci pee heirs Limits
NOTE
If the response does not meet the specified response
limits, the head should be checked for accumulated
oxide or dirt. Then, if no dirt is found, the head
azimuth should be readjusted.
7-1-5. SIGNAL TO NOISE RATIO —PLAYBACK—
—
Place the deck in the PLAY-PAUSE mode.
Read the indication on the VTVM.
The VTVM should indicate -52 dB minimum (1.94
mV maximum).
This corresponds to a signal-to-noise ratio of 47 dB
(minimum): difference between residual noise —52 dB
and the specified output level —5 dB (435 mV).
NOTE
Since the polarity of the AC plug has some effect on
the signal-to noise ratio, the plug can be reversed in
the wall socket when checking the signal-to-noise
ratio. The’ worse case value should be within the
indicated value above.
Specification: 47 dB (minimum)
18
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CONNECTION: See Fig. 7-4 (B) :
SWITCH & CONTROL SETTING: '
4 Hy
'
2 j
i
3 NORMAL '
T-470
OUTPUT Control:
Specified Control Setting (See 7-1-2)
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FM/ COPY ~ SOURCE