STARTING WITH S5
Audial S5 is a reference quality, TDA1541A based non-
oversampling D/A converter. It is easy to use, and it
requires no special maintenance or care. It achieves
claimed technical performance (distortion, frequency
response, etc) right from the start, however it needs a
couple of weeks of burning in to perform its best in
subjective terms.
Please note that the TDA1541AD/A converter chip is a
classic TTL chip architecture, which dissipates
somewhat more power than it is usual for devices of
this kind these days. Hence it is not recommended to
leave the S5 permanently powered up. On the other
hand, that is not needed, either. Once the S5 passes its
initial burning in, it is generally enough to have it
powered up for about half an hour before critical
listening.
Mains cable shipped with S5 is the industry standard
grade. It is however generally recommended to use
high quality, preferably solid core cables, everywhere
in the audio system, and this suggestion applies to the
mains cable too.
An RCA to BNC adapter is shipped too, for the
customers’ convenience, but it is highly recommended
to use real 75 Ohm BNC plugs. Regardless of what you
might be told from time to time, the RCA can not meet
this requirement.
The S5 front plate sports the mains switch and input
selector, with the mains power LED indicator in
between.
All the connectors, along with the direct input mode
switch and S/PDIF PLL mode switch are located on the
back plate.
DIGITAL INPUTS AND OUTPUT
The S5 has four inputs: S/PDIF electrical, S/PDIF
optical, PCM (I2S) direct, and USB.
The S/PDIF electrical input is the real 75 Ohm BNC,
transformer coupled input. The ground of the S/PDIF
line is coupled to the DAC ground by a 0.1 uF capacitor.
With both electrical and optical S/PDIF sources, the S5
supports sampling frequencies up to 96 kHz.
S/PDIF receiver uses a PLL to lock to the source, and
thus retrieve the sampling clock from it, and it can lock
either to the S/PDIF data, or to the preamble. The PLL
mode switch is located at the back plate. Please note
that, to change the PLL mode, the DAC must be reset.
This is achieved by turning it off, and waiting for at least
10 seconds, before powering it up again. Otherwise,
the PLL mode change will not take the effect.
The PCM direct input uses an HDMI connector, but
please note that the signals here are carried in their
raw form, so they are not codded, and hence not
compatible with HDMI protocol. This input can accept
either I2S or Philips simultaneous data protocol, as set
by the switch at the back plate.
The S5 USB input stage operates as an asynchronous
(master) USB device, with its own master clocks for D/A
conversion, and two low jitter clocks are included. A
22.5792 MHz works with 44.1/88.2/176.4/352.8 kHz,
and 24.576 MHz works with 48/96/192/384 kHz audio
sampling frequencies. This way the unit achieves a
clean clocking scheme, and all the audio clock signals
in the system are generated only by frequency
dividing, and not by using PLL synthesizers.
The USB stage also provides galvanic decoupling
between the USB and D/A stage, thus also separating
PC from audio circuits.
In addition, the USB stage supports four channel
operation. The first two channels are always converted
by the S5 D/A stage, and are available as analog
outputs, while the third and fourth channels are
available as digital signals, decoded and output as
serial PCM i.e. Philips simultaneous data protocol, at
the HDMI output connector. Consequently, two S5
DACs, with an HDMI cable connecting this output to
the other S5 DAC PCM direct input, can make a four
channel USB DAC.
The pinout and voltage specifications for this PCM
output and PCM (I2S) direct input are provided
separately.
5
Audial S5
