Akai GX-225D User Manual

ll. MEASURING METHOD
1, TAPE SPEED DEVIATION
Frequency
counter
input
GX-225D
Line output
Fig. 1
As shown in Fig. 1, connect a Frequency Counter to
the Line output. Playback a 1,000 Hz pre-recorded
test tape. Take a frequency counter reading at the
beginning, middle, and end of tape winding during
playback. The maximum value of these respective
readings will represent tape speed deviation.
2. WOW AND FLUTTER
GX-225D Wow and Flutter
Line output Meter input
Fig. 2
Method A
As shown in Fig. 2, connect the Line output to the
Input of a Wow and Flutter Meter. Playback a
3,000 Hz pre-recorded test tape and take a wow and
flutter meter reading at the beginning, middle, and
end of tape winding. The maximum yalue of these
respective readings will represent the wow and flutter.
Method B
Supply a 3,000 Hz sine wave signal from an Audio
Frequency Oscillator and make a recording on a
blank tape at the beginning, middle, and end of tape
winding. Rewind and playback the resultant signal.
Measure wow and flutter with a Wow and Flutter
Meter. (The wow and flutter value of Method B will
be close to twice that of Method A.)
3, FREQUENCY RESPONSE
GX-225D
Line
Frequency input ane
Oscillator
ae 8
output
High Sensitivity
V.T.V.M,
Fig, 3.
For
measuring
frequency
response,
connect
instru-
ments
as
shown
in
Fig.
3
and
proceed
as
follows:
1) Supply a 1,000 Hz sine wave to the Line input
from an Audio Frequency Oscillator through’ an
Attenuator.
2)
Set
recorder
to
recording
mode
and
turn
recording
level
contro!
volume
and
line
output
level
control
volume
to
maximum,
Adjust
attenuator
to
obtain
a+4
dB
V.T.V.M.
reading.
3)
Under
conditions
described
in
2)
above,
re-adjust
attenuator
so
that
the
Line
Output
is
—16
dB,
and
record
30
to
22,000Hz
at
7-1/2
ips
spot
fre-
quencies.
4)
Rewind
the
tape
and
playback
from
the
beginning.
Take
V.T.V.M.
spot
frequency
readings
and
plot
values
on
a
graph.
.
NOTE:
When
measuring
frequency
response,
new
tape
should
be
used.
4, SIGNAL TO NOISE RATIO
GX-225D High Sensitivity
Line output VIVM,
Fig. 4
As
shown
in
Fig.4,
connect
a
High
Sensitivity
V.T.VM.
to
the
Line
output.
Playback
a
250
Hz
“Q”
VU
pre-recorded
test
tape
and
mieasure
the
output.
Then
remove
the
tape
and
measure
the
noise
level
under
the
same
condition,
Convert
each
of
the
measured
values
into
decibels.

Akai GX-225D Specifications

General

Brand	Akai
Model	GX-225D
Category	Tape Deck
Language	English