Teac A-6300 - Page 31

SIGIMAL-TO-NOISE RATIO
PLAYBACK
IMPORTANT
OUTPUT controls should be at the Specified Output Level Settings.
The signal-to-noise ratio must meet factory standards. The values
given are obtained using an unweighted Test Set (M-826A), with
the supply and take-up motors having voltage applied but not rotat¬
ing.
1. Thread a blank YTT-8013 tape on the
unit leaving the tape outside the cap¬
stan and pinch roller.
2. Hold the supply reel stationary and
depress the play ( ► ) button.
3. The Test Set connected to the OUTPUT
jacks should indicate -58 dB or less.
4. This corresponds to a signal-to-noise
ratio of 50 dB (difference between
residual noise -58 dB and specified
output level -8 dB for 1% THD).
NOTE
Tape SPEED at LOW (7-1/2 ips) and play¬
back head switch at 2 track position.
Fig. 11-10 Signal/Noise Computation
OVERALL -
IMPORTANT: Clean and demagnetize the heads before proceeding.
It is extremely important that all tests described in the pre¬
ceding paragraphs have been completed and that all controls
are left at their specified settings.
1. Thread a blank Test Tape YTT-8013 on the unit.
2. Remove the AF oscillator from the LINE IN jacks.
3. Place the unit in the RECORD mode with "no signal" applied.
Note the point on the index counter where recording begins.
4. Rewind the tape to the beginning point and play it back.
5. The noise level as indicated on the Test Set should be -56 dB
or less. NOTE: Tape SPEED at LOW.
NOTE: Bias, erase and playback amplifier noise are all included
in this measurement. All frequencies between 20 Hz and 26 kHz
are measured unweighted.
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