Frequency Characteristics Check; Hpf Check; Channel Equalizer Characteristics Check - Yamaha MG12/4 Service Manual

Table 2-6-4 Input Terminal STEREO IN [dBu ]
INPUT INPUT CH
t
9L, 11L (13L, 15L)
PHONE JACK
y
10R, 12R (14R, 16R)
9L, 11L (13L, 15L)
PIN JACK
10R, 12R (14R, 16R)
Table 2-6-5. Input Terminal RETERN L, R [dBu ]
INPUT INPUT Level
u
L/MONO
i
R
Table 2-6-6. Input Terminal 2TR IN L, R [dBu ]
INPUT INPUT Level
o
L
-27.8
!0
R
* In measuring the C-R OUT L/R and PHONES L/R level, set the C-R/PHONES Output and Meter Select switch to 2TR IN.
2-7. Frequency Characteristics
In the signal routes of the Table 2-6-1 to 2-6-6 indicated with q to !0 , the 20Hz and 20kHz frequency response of each output
shall be within the range of 0 dB +1/-2.5 dB compared to the 1kHz (0dB).
* The 20Hz level when the GAIN volume is Max shall be within the range of 0 dB +1.0/-4.5 dB compared to the 1kHz (0dB).
* In the route q, check every OUT when the signal is fed to CH1, and check only the ST L OUT when the signal is fed to CH2
and other channels.
* In the route r, check only the ST L OUT and the ST R OUT.
2-8 HPF
In the state of the Table 2-6-1 and 2-6-2, feeding 80 Hz -36dBu signal, and setting the GAIN to MIN, the STEREO L OUT level
obtained when the / — 80 switch is set to ON shall be within the range of -3 dB +2/-2 dB compared to the level obtained when the
switch is set to OFF.
2-9 Channel Equalizer Characteristics
In the state checked in 2-2 above, check the output level obtained at GROUP 1 OUT in the case of CH INPUT and ST CH
INPUT L and at GROUP 2 OUT in the case of ST CH INPUT R when LO, HI and MID of INPUT are moved respectively. Its
level of each frequency shall be within the range specified in the table 2-9-1 compared to the output level obtained when the EQ
gain control is center click position.
If it is without the range, search the frequency, within the range of +/- 20%, of that the level is within the range of Table 2-9-1.
Table 2-9-1 [dB ]
EQ control EQ GAIN
MAX
HI
MIN
MAX
MID
MIN
MAX
LO
MIN
INPUT
ST L OUT ST R OUT GROUP1 GROUP2
Level
-30 +4 +/- 2
—
+4 +/- 2
—
ST L OUT ST R OUT
+16 +/- 2 +16 +/- 2
0
— +16 +/- 2
ST L OUT ST R OUT
0 +/- 2
— 0 +/- 2
Applied frequency
10kHz
2.5kHz
100Hz
— +4 +/- 2 —
+4 +/- 2 — +4 +/- 2
— — —
+4 +/- 2 — —
AUX1 OUT AUX2 OUT
+15 +/- 2 +15 +/- 2
+9 +/- 2 +9 +/- 2
C-R OUT L C-R OUT R
— 0 +/- 2
— 0 +/- 2
Variation width
+12 +/- 2
-12 +/- 2
+15 +/- 2
-15 +/- 2
+12 +/- 2
-12 +/- 2
AUX1
AUX2
PRE OFF PRE ON
+3 +/- 2 -7 +/- 2 +3 +/- 2
+3 +/- 2 -7 +/- 2 +3 +/- 2
— — —
— — —
PHONES L PHONES R
— -11.5 +/- 2
— -11.5 +/- 2
MG12/4
MG16/4
C-R OUT
*2
0 +/- 2
—
—
—
—
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