Alto APM80.1000 Service Manual page 24

OUT is equal to 0dBu and THD+N : <0.2%.
Press the PAD switch for one time when testing; see whether the output range has
20dBu variation.
1. CH1~CH6 MIC Socket:-40dBu (±3dBu).
2. CH7-8, CH9-10 MIC Socket:-37dBu (±3dBu).
3. CH1~CH6 LINE Socket:-20dBu (±3dBu). Note: The AP output is balanced.
4. CH7-8 Left and Right LINE Socket, CH9-10 Left and Right LINE Socket: -17dBu
(±3dBu).
Pay attention to this point, when input from the RIGHT, the MAIN LEFT and RIGHT all
have outputs; When input from the LEFT, only the MAIN LEFT has output (Note: The
AP output is unbalanced.)
5. STEREO RTN: 7dBu (±3dBu).
The AP output is unbalanced.
6. TAPE IN at CH9-10: 0dBu (±3dBu).
7. TAPE IN at MAIN:-20dBu (±3dBu).
3. 3-BAND EQ TEST of Each Channel
Input -40dBu BAL signal from each channel respectively, adjust the LEVEL and make the
MAIN OUT is equal to 0dBu, the AP scan setting is as follows:
1. When the HIGH, MID and LOW are turned to the midpoint, the curve is as shown in the
following figure 1.
2. When the LOW and HIGH are minimum, the MID is maximum, the curve is as shown in
the following figure 2.
3. When the LOW and HIGH are maximum, the MID is minimum, the curve is as shown in
figure 3.
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