Sony SRP-X700P - Manual (Page 44)

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Momentary
In the parallel remote, it means a momentary operation for switch.
For example, when a button of switch is pressed, the switch becomes ON only during
the button being pressed. When the button is released, the switch becomes OFF.
Power Amplifier
It amplifies audio signal to drive such as a loudspeaker.
Digital Amplifier
SRP-X700P incorporates PWM (Plus Width Modulation) amplifier which amplifies
signal with a devices being rapidly switched on and off.
It has much higher efficiency (much less power consumption) and lighter weight than
analog Class A/B amplifier.
Maximum output power (maximum useful output power)
It is the maximum output power being able to output certain time (generally shorter
than ‘Rated output power’) with a certain distortion value (generally higher than
‘Rated output power’), by measuring with sine waves of certain frequencies and
certain impedances.
The SRP-X700P outputs 150W per channel with 4 – 16 ohms load.
Rated output power
It is the expression for average output power usually used in consumer or professional
power amplifiers.
Amplifier can output average power of rated frequency bandwidth (for example, sine
waves at various frequencies), continuously (for example not less than 5 minutes), at
rated load impedance and rated total harmonic distortion.
The specified values of bandwidth, load impedance and THD are ge nerally indicated
in case the rated power is expressed on its specifications sheet.
Testing for ‘The Continuous Average Power Output’ is defined by EIA RS-490.
70 V (70.7 V)
It is one of the voltages for high- impedance loudspeaker distribution which makes use
of amplifier providing constant nominal output voltage.
Another representative voltages are 25 V, 100 V or 140 V.
Output of amplifier is converted to high- impedance to drive many speakers.
Following basic formula is applied for operation of 70 V (or, 100 V, etc) system.
P=E
2 /R (P= power, E=voltage, R=resistance)
For example for SRP-X700P equipped with 70 V output of 150 W, in case of using a
7.5 W (670 ohms) speaker, up to 20 units can be parallel connected to the X700P. By
applying formula above, 150 [P]=70.7
2 [E 2 ]/(670/20) [R].
670/20 means parallel connection of 20 speakers of each 670 ohms.
Its advantage is simple wiring due to parallel connection, different level setup
capability for each speaker with taps, keeping operating remained speakers in case of
failure of one speaker due to parallel connection, etc.