AYRE QB-9DSD - Manual (Page 10)

An introductory guide to setting up your computer
is available at the Ayre website at:
www.ayre.com/usb.htm
DSD over PCM (DoP)
In addition to the standard method of encoding
audio signals as digital information (PCM, or Pulse
Code Modulation), another system also exists, called
DSD by Sony who used it for their SACD format.
(Technically, it is simply a specific form of PDM or
Pulse Density Modulation.) While it is quite
difficult to transfer (“rip”) SACDs to your computer
for music playback, there are now a few record labels
that sell music file downloads in the DSD format.
Since most computer operating systems will not
directly handle DSD-encoded music files, an
industry consortium has developed a method of
“packetizing” the DSD data as PCM words. This
process is called “DSD over PCM” or DoP, and
requires a music playback application that is
compatible with DoP, as well as a compliant USB
D/A converter, such as the QB-9
DSD . The QB-9 DSD
will play back DoP files in their native DSD format.
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