Sony STR-DA9000ES - Manual (Page 6)

ES Receivers v1.0 Page 6
The conventional A/V receiver is anything but simple. The signal must
run through a gantlet of processes and stages.
The Sony S-Master Pro amplifier is dramatically different. There is no
Digital-to-Analog (D/A) converter. Instead, the amplifier accepts all digital signals
directly, whether they're multi-bit Pulse Code Modulation (PCM) or 1-bit Direct
Stream Digital™ pulses from Super Audio CD. Even analog inputs are converted
to DSD. The output of the S-Master Pro amplifier goes through a single Low
Pass Filter to provide the wattage that drives the speakers. In this way, the
signal remains digital until the last possible instant.
The Sony S-Master Pro amplifier dramatically simplifies receiver design.
And in high fidelity, simpler is better.
The S-Master power amplifier generates a 1-bit pulse stream to switch
pairs of MOS FET power output transistors on and off. The resulting output has
more than enough wattage to drive a loudspeaker.
The output transistors act like an on/off switch for the power supply
voltage. The Low Pass Filter (LPF) converts the amplified pulses to a
smooth, continuous analog waveform.
The S-Master 1-bit pulse stream has much in common with the Direct
Stream Digital signal that Sony developed for Super Audio CD. If you look
Digital Signal
Input
(Digital)
DSP
S-Master
Power Amplifier
LPF
Analog Signal
Speaker
Output
Digital Signal
Input
(Digital)
DSP
D/A
convert
LPF
Volume
Control
Analog
Power
Amp
Analog Signal
Speaker
Output