Yamaha XP-7000 Service Manual page 40

XP7000/XP5000
4. Preparation for BRIDGE mode
Attenuator
Input terminal
MODE switch
GAIN switch
HPF switch
Load resistance
Make connections as shown below and measure the output voltage at each point.
XP7000
XP5000
5. Inspection
5.1 Gain
Input a 1 kHz, -10.0 dBu signal and check that +28.0 ± 1.0 dBu output voltage is obtained.
5.2 Frequency characteristics
Input 20 Hz, 1 kHz, 20 kHz, -10 dBu signals and check that the output voltage obtained is within -0.5 ± 0.5 dBu at 20 Hz and
20 kHz as compared with the output voltage at 1 kHz.
5.3 Distortion
Input 20 Hz, 20 kHz signals to the input terminal and check that the distortion is 0.1% or less when the output voltage as
specified in the table below is obtained.
This inspection should be completed within 30 seconds.
XP7000 (U/T/A)
149.68 V
5.4 Output noise level
Shunt 2 pin (hot) and 3 pin (cold) of input terminals with 600 ohms.
Measure the noise level at the output terminal and check that it is -60 dBu or less.
Next, set the attenuator to MIN and check that the noise level is -65 dBu or less.
Use a DIN AUDIO filter for this measurement.
40
: "0" (MAX) Only channel A is valid.
: XLR connector 2PIN-HOT/3PIN-COLD/1PIN-GND
: BRIDGE
: 32 dB
: OFF (both channels)
: 8 + 8 ohms +/- 1%
A+
8 ohms
or
8 ohms R
B+
XP7000 (H/B/K/O)
144.24 V
INPUT+
R
MEASURING
INSTRUMENT
INPUT-
XP5000
126.50 V