Teac A-3440 - Record Level Set; Frequency Response - Overall; Signal-to-Noise Ratio - Overall

11
9.
10.
il.
12.
11
OSCILLOSCOPE
AC Voltmeter
under TEST
1-621
Fig. 8-10 Test Connection for Recording Check
3. RECORD LEVEL SET
Apply a 400 Hz signal at —12 dB (195 mV) to the LINE
IN jack.
Check that the LINE and OUTPUT Controls are still
at their specified positions.
Begin recording.
Adjust REC LEVEL R206 for —8 dB (308 mV) at the
OUTPUT jack.
4 FREQUENCY RESPONSE — OVERALL
NOTE: To avoid saturation of the tape these checks should
+ +
os 5
RESPONSE IN dB
*
I
ES
20
be made at least 10 dB (—10 VU) below the speci-
fied input level (ie. —22 dB/61.5 mV) for LOW
Speed and at 0 VU for HIGH Speed.
Any bias signal feeding into the test equipment
should be filtered out by adjusting the external
bias trap.
Tape SPEED Selector SW ......... LOW
. Apply a signal swept from 40 Hz to 20 kHz at —22 dB
(61.5 mV) to the LINE IN jack and record on a blank
TEAC YTT-8013 tape.
. During recording monitor the off-tape signal and adjust
Equalization REC EQ L102 for readings within the res-
ponse limits.
FREQUENCY IN Hz
Fig. 8-11 Frequency Response —Overall— 1
Tape SPEED Selector SW........ HIGH
3. Apply a signal swept from 40 Hz to 22 kHz, this time
at a level of —12 dB(195 mV) and check that the response
is within the limits indicated.
4. If REC EQ L102 are adjusted check LOW section again.
NOTE: If the response is not uniform, the heads should be
checked for accumulated dirt and oxide and the
bias adjustment should be repeated.
RESPONSE IN dB
FREQUENCY iN Hz 121275
Fig. 8-12 Frequency Response —Overall— 2
11-5 SIGNAL-TO-NOISE RATIO — OVERALL
5. OUTPUT and LINE Controls should be at the specified
positions.
6. Remove the AF oscillator from the LINE IN jack.
. Place the deck in the Record mode with no signal applied.
. Note the point on the Index Counter where the record-
ing begins.
9. Rewind the recorded tape to the beginning and play it
back.
10. The noise levels read on the VTVM should be as follows:
co~
Noise Level
—54 dB (1.55 mV) or better
—53 dB (1.73 mV) or better
NOTE: This —53 dB/54 dB corresponds to a S/N ratio of
45 dB/46 dB (minimum), being the difference
between the residual noise and the specified out-
put level of —8 dB.
Tape Speed
LOW (7-1/2 ips)
HIGH (15 ips)
The measuring method used to establish the S/N
spec. in the catalogue and the owner’s manual is
different and these figures will not be the same.