Teac A-650 - Playback Performance Verification (Continued); Playback Signal-to-Noise Ratio Measurement; Playback VU Meter Calibration

6-2-4. SIGNAL TO NOISE RATIO -PLAYBACK-
Preparations:
Connection. See Fig. 6-6 (B) on page 22.
Switch Setting:
1.
BIAS
EQ LIMITER DOLBY NR
3 OUT
OUT
4.
6-2-5. VU METER CALIBRATION -PLAYBACK-
P reparations:
Specification. +3 VU ( CC ) Connection: See Fig. 6-6 (B) on page 22.
Switch Setting:
BIAS
EQ
LIMITER
3 OUT
6-2-6. HEADPHONE OUTPUT LEVEL CHECKS
VTVM
Preparations:
Specification. -15.7 dB ± 2 dB (103 mV
163 mV)
p
o o
rtsi fitsisTwn-
Switch Setting:
BIAS LIMITER
DOLBY NR
EQ
3
OUT
OUT
23
2.
3.
Load and play a completely erased or degaussed TEAC
MTT-501 test tape.
Read the indication on the VTVM.
The VTVM should indicate -51 dB minimum (2.18
mV maximum).
This corresponds to a signal-to-noise ratio of 46 dB
(minimum): difference between residual noise -51 dB
and the specified output level — 5 dB (435 mV).
Load and play a TEAC MTT-1 50 test tape.
Measure the level across the test load resistor.
Load and play a TEAC MTT-1 50 test tape.
Adjust VR1 03/203 for +3 VU ( HI ) on the VU meter.
Control Setting:
OUTPUT: Specified Setting (See 6-2-2)
Control Setting:
OUTPUT: Specified Setting (See 6-2-2)
Control Setting:
OUTPUT: Specified Setting (See 6-2-2)
1.
2.
1.
2.
NOTE
Since the polarity of the AC plug has some effect on
the signal-to-noisc 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.
INPORTANT
VU meter calibration must also be conducted after
that of MONITOR PERFORMANCE (see 6-3-3 on
page 24) is completed.
DECK under TEST
PHONES
O'*"
Specifications:
CrO 2 & Fe-Cr tapes. 48 dB (minimum)
Hi-Fi tape: 46 dB (minimum)
NOTE
An 8 ohm non-inductive resistor should be used as
the test load resistor.
DOLBY NR
| OUT
Fig. 6-8 Connection