Teac A-5500 - Signal-To-Noise

PLAYBACK
SIGNAL-TO-NOISE RATIO
IMPORTANT
OUTPUT controls should be at the Specified Output Level Settings.
The signal-to-noise ratio mist 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 rotating.
The values are with reference to a 3% THD Peak Recording Level.
vvyYv Vv Vv
1. Thread a blank YTT-8003 on the unit. pens Regs,” et GNIS ation weer
2. Place the unit in the PLAY mode ( »® ) Eas jenn an
and engage PAUSE. ies an
3.
The
Test-Set
connected
to
the
OUTPUT
~8a8
gs
cn
nase
pee
paeniiey
jacks should indicate -56 dB or less. l mie
4, This corresponds to a signal-to-noise 5 ia a
ratio of 48 dB (difference between 2 ae
residual noise -56 dB and specified 3 af
output level -8 dB for 1% THD). 5 Z
For a 3% THD signal-to-noise ratio, :
-6 dB is added, giving 54 dB (3% THD 2
is 6 dB above 1% THD level). ee eo :
S4d8_ S608 : es ‘ “|
= Pe RESIDUAL NO} ras é 5
hhh ‘cue tor? 3
Fig. 11-12 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 YIT-8003 tape 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 -47 dB
or less (19 cm-7-1/2 speed).