Yamaha PX10, Service Manual

Page: 54 / 148

54
PX10/PX8/PX5/PX3
Therefore, the connection method with the interchangeability
that can correspond to any amplifier output method is
preferable. The above-mentioned connection
method can be compatible for the amplifier output with
the single end output and the bridge output, and apply any
audio analyzer.
Please shorten between the ampli fi er to be measured and
the analyzer to suppress the in fl uence of turbulence and
connect it. Moreover, please make to fl oating
without fail for the output.
(One on the load side is not grounded. When monitoring
with the oscilloscope, it does based on the chassis
playground. )
2. Electric characteristics
2-1. Preparation
2-1-1. Load resistances
The load resistances for each output terminals are as follows.
8 Ω MODE
：
8ohms±1% (Rated 750W or more)
2 Ω MODE
：
2ohms±1% (Rated 250W or more)
2-1-2. Input Signal
Unless otherwise speci fi ed, the input signal should be 1kHz sine wave.
The input signal impedance should be 100
〜
150 ohms.
0dBu is referenced to 0.775Vrms.
2-2. Inspection
2-2-1. Gain
Measurement condition Criteria
Select “Analog > CFG1
（
+14dBu
）
” with Service inspection mode.
Measured mode
／
8 Ω MODE
The sine wave of 1kHz -6dBu is input to the input terminal,
and the output level of SP OUT is measured.
All channel
PX10 21.3dBu ± 2dB
PX8 20.3dBu ± 2dB
PX5 18.3dBu ± 2dB
PX3 16.1dBu ± 2dB
Between channel
± 2dB
Select “Analog > CFG2
（
+4dBu
）
” with Service inspection mode.
Measured mode
／
8 Ω MODE
The sine wave of 1Hz -6dBu is input to the input terminal,
and the output level of SP OUT is measured.
All channel
PX10 31.3dBu ± 2dB
PX8 30.3dBu ± 2dB
PX5 28.3dBu ± 2dB
PX3 26.1dBu ± 2dB
Between channel
± 2dB
Flow of signal and output method of PX amplifi er
I
n PX ampli fi er, the type of output is the BTL fi xation. (Fig. 2)
〈
Fig. 2
〉