dCS 974 User Manual

Manual for Software Version 1.0x

dCS Ltd

May 2001

 

 

 

 

 

 

 

 

 

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-2or 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

88.2kS/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:

Manual part no: DOC1241121A1

Page 45

Document No: OS-MA-A0124-112.1A1

Contact dCS on + 44 1799 531 999

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(inside the UK replace + 44 with 0)

web site: www.dcsltd.co.uk