Teac A-4300SX - Page 17

8-18 RECORD LEVEL SET
14. Apply 400 Hz signal at ~8 dB (308 mV) to the LINE IN
jacks.
Be sure the Line and Output controls are still at their
BIAS and EQ SW
23:
24.
Apply signals swept from 40 Hz to 14 kHz to the unit
while recording on a blank TEAC YTT-8023 Test Tape.
Repeat the above procedure for HIGH, using a signal
20.
21.
. Apply signal swept from 40 Hz to 24 kHz, —28 dB (30.8
previously set positions.
15. Begin recording.
16.
PUT jacks.
8-19 FREQUENCY RESPONSE —OVERALL—
NOTE: To avoid saturation of the tape these checks should
be made at least 20 dB below the specified input
level.
Any Bias signal feeding into the test equipment
should be filtered out by adjusting the external
Bias Trap.
BIAS and EQSW .... 2... ee ee ee 1
Tape SPEEDSW...... 3-3/4 ips (9.5 cm)
. Apply signal swept from 40 Hz to 16 kHz, —28 dB
(30.8 mV) to the LINE IN jacks and record on a blank
TEAC YTT-8003 Test Tape.
During recording, monitor the Tape signal and adjust
equalization L-301/L-303 for readings within the Re-
sponse Limits charts. See Fig. 8-10 below.
Change the Tape SPEED SW to HIGH position.
mV) and while monitoring the off-the-Tape signal check
for readings within the Response Limits charts. See Fig.
8-10 below.
| Hil
fs fof tt tf +—
3-3/4 ips
mooes titi it
| +5
+4
+3
gra-——- + ‘ae 3
z
40 4 es
z au
8-2
#
“a = |
++ tt ttt
4 ‘wo 125 400 500 mK 5K OK 14K 16K 50K
FREQUENCY IN Hz
RESPONSE IN df
Fig. 8-10 Frequency Response — OVERALL — 1
Adjust VR-303/VR-306 for —8 dB (308 mV) at OUT-
swept from 40 Hz to 22 kHz. Refer to Response Limits
in Fig. 8-11 below.
NOTE: If the response is not uniform, the head should be
cleaned of accumulated oxide and dirt. Then repeat
the Bias adjustment procedure by VR-401 (both
channel).
THT
3-3/4 ips
* 2
+ n
No
RESPONSE IN dB
RESPONSE IN dB.
1
Ey
FREQUENCY IN Ha
Fig. 8-11 Frequency Response —- OVERALL — 2
8-20 SIGNAL-TO-NOISE RATIO —OVERALL—
1. Output and Line controls should be at the specified
positions.
2. Remove the AF oscillator from the LINE IN jacks.
3. Place the deck in the Record mode with “‘no signal”
applied. Note the point on the index counter where
recording begins.
4. Rewind the tape (YTT-8003) to the beginning pointand
play it back.
5. The noise level as indicated on the VITVM should be
readings listed below.
HIGH (7-1/2 ips) .......... —56 dB
LOW (3-3/4ips) .........-. —54 dB
6. This -56 dB/—54 dB corresponds to the Signal-To-Noise
Ratio
of
48
dB/46
dB
(minimum):
the
difference
between
residual
noise
of
—56
dB/—54
dB
and
the
specified
p
ut-
put
level
-8
dB.
—8
dB
reference
level
is
also
appliable
following
measurements.