Yamaha PX10, Service Manual

Page: 53 / 148

53
PX10/PX8/PX5/PX3
1. Measurement condition
1-1. Environment
Normal temperature: 5 to 40 degrees
Normal humidity: 30 to 90%
Note) [the following measurement conditions are
permitted if measurement result is in the inspection
standard. (Temperature: 5 to 40 degrees, Humidity: 20
to 90%) But measure it again at the normal temperature
and normal humidity when it varies from the inspecting
standard.]
1-2. Power Source
Destination Voltage Frequency
J 100V +2/-0% 50Hz
U/T/BRA 120V +2/-0% 60Hz
E/B/K/CHN 230V +2/-0% 50Hz
1-3. Measuring instruments
The measuring instruments shall have enough accuracy
and precision to measure the specifications of each
characteristic to be inspected.
The input impedance of the measuring instruments shall be
100kohms or more.
Use the measuring instrument that can measure the
speci
fi cation value described in this speci fi cation.
1-3-1. Input terminals
The XLR and PHONE-JACK are used to connect input
signals. It shall be a balanced input.
A XLR terminal performs measurement without
directions.
1-3-2. Output terminals
The SPEAKON, PHONE-JACK and 5WAY terminal are
used to connect output loads.
A SPEAKON terminal performs measurement without
directions.
1-3-3. Filter for measurement
Use AUX-0025 Filter for the measurement of 2-2-
1
. Gain
to 2-2-1
4
. Maximum Output (BOOST Mode).
Use the low-pass filter of 20kHz according to the
measurement item.
1-3-4. Connection
Refer to the “1-2. How to connect” (Page 32) of INSPECTION
section.
1-4. Caution for measurement environment
Connected chart when classD ampli fi er (PX ampli fi er) is
measure
Insert AUX-0025 between classD ampli fi er and the audio
analyzer when you measure classD ampli fi er.
Reason why insertion of AUX-0025 is indispensable
The high frequency noise caused by the switching drive is
included in the output signal of classD ampli
fi er.
However, the audio analyzer doesn't generally assume
the high frequency. In a word, there is no tolerance to the
high frequency.
Therefore, there is a possibility that the audio analyzer
doesn't operate normally when the high frequency is not
removed with AUX-0025.
The reason to recommend the above-mentioned
connection method
Figure 2 is the block diagram of the output composition
of the PX ampli
fi er.
The output of classD ampli fi er is not necessarily limited
the shingle-end output.
Moreover, it is possible to understand that reversing of the
phase by HOT and COLD from the block diagram.
The output method of a recent classD amplifier takes
various forms like this.
MEASUREMENT