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dCS 974 User Manual Manual for Software Version 1.0x
dCS Ltd May 2001
Manual part no: DOC1241121A1
Page 45
Document No: OS-MA-A0124-112.1A1
Contact
dCS
on + 44 1799 531 999 email to: more@dcsltd.co.uk
(inside the UK replace + 44 with 0) web site: www.dcsltd.co.uk
For a 2 Pass conversion, convert the input to an intermediate sample rate and
either feed it direct into another dCS 974 or record the result, then convert from
the intermediate sample rate to the required sample rate. You can always
choose one of 44.1 kS/s or 48 kS/s as the intermediate sample rate, so you can
record the intermediate pass on most recording devices.
However, it is best to use the highest possible sample rate for the intermediate
pass, if your recording device can take it. For example, to convert from 192 kS/s
to 12 kS/s, first convert from 192 kS/s to 96 kS/s, and then convert from
96 kS/s to 12 kS/s. Use of two dCS 974’s avoids intermediate storage.
Output Mode
For DSD output, select DSD SDIF-2 or DSD SDIF-3, and the unit will make the
appropriate changes. The unit supports DSD out with either DSD or PCM in.
DSD output includes a DSD DC blocking filter. All signals in DSD or PCM will
have their DC filtered out. When set to either DSD output mode, a DSD Quad
signal appears on four output cables – AES 1, AES 2, AES 3 and AES 4. The 3
SPDIF outputs all carry identical AES streams with no data – they may be used
for synchronisation.
For PCM output, select Dual AES to output a 192kS/s, 176.4kS/s, 96 kS/s or
88.2 kS/s AES3 signal on two output cables – AES 1 and AES 2 (or AES 3 and
AES 4). In this mode, the AES Clk Output and 3 SPDIF outputs all carry
identical AES streams with no data – they may be used for synchronisation. The
SDIF Clk Output sends Wordclock at the same rate as on AES 1, do not use
the SDIF data outputs while in Dual AES mode.
For PCM output, select Quad AES to output a 192kS/s or 176.4kS/s AES3
signal on four output cables – AES 1, AES 2, AES 3 and AES 4. In this mode,
the AES Clk Output and 3 SPDIF outputs all carry identical AES streams with
no data – they may be used for synchronisation. The SDIF Clk Output sends
Wordclock at the same rate as on AES 1, do not use the SDIF data outputs
while in Quad AES mode.
Otherwise, set to Normal for single wire outputs on AES 1, AES 2, AES 3 &
AES 4, the three SPDIF outputs and the SDIF-2 output.
For PCM out, the unit can have PCM or DSD in.
Filter
The dCS 974 offers a choice of filter for use on some of the more popular in/out
combinations. The filters offer differing responses. For PCM outputs, Filter 1 in
each case offers the sharpest cut-off and no or least aliasing, but longest
energy smear. Filter 4 gives the gentlest roll-off (usually with significant aliasing)
but the shortest transient response with least smear. For DSD output, the
differences are not so great – the responses are given in the section dCS 974
Performance Curves, page 94. The conversions that offer multiple filters are
as follows: