The DSD I/O Module type PREV039/9/1 provides eight channels of ‘Direct Stream Digital’ input and output for the ADA-8XR. The DSD interface format carries an over-sampled one-bit representation of the audio signal as delivered on Super Audio CDs (SACDs).

The DSD I/O Module can transact the DSD data in either SDIF 2 (sometimes known as DSD RAW) or SDIF 3 formats, using coaxial cables via a breakout squid, and optionally in the MAC DSD / SuperMAC format using a CAT5E cable.

When combined with the ADA-8XR’s Analogue Line Input and Output modules, the DSD I/O Module provides eight channels of analogue-to-DSD and DSD-to-analogue conversion. The Module also allows for PCM to DSD and DSD to PCM conversion where a PCM-type I/O Module is fitted, such as an AES3 I/O Module. In this case, PCM synchronous sample rate conversion can also be performed between the PCM input and output for all eight channels.

The DSD I/O Module supports three different interface standards.

The male 25-way ‘D’ connector is used for either SDIF 2 or SDIF 3 formats, selected using the ADA-8XR's menu system. You should check the interface format of the connected equipment to ensure correct operation, however no damage will result from a logical format mismatch as the interface is electrically the same in both cases. The input and output interface formats of the DSD Module are individually selectable. An optionally-supplied 'squid' breaks out the 25 way 'D' to eight blue BNC plugs for the DSD inputs, eight red BNC plugs for the DSD outputs, and one black BNC plug for the interface clock output. To assist in custom cabling applications, the pin-out of the squid is shown in section 8.10.6.

When the DSD I/O Module is used in conjunction with a PCM digital I/O Module (for example an AES3 I/O Module) it becomes possible to perform direct digital PCM to DSD and DSD to PCM conversion at any of the ADA-8XR supported sample rates. Furthermore it becomes possible to perform PCM to PCM conversion at any combination of input and output rates.

PCM DSD conversion can be achieved by assigning the PCM I/O Module as the input to a Path and the DSD I/O Module as the output. Conversely, to perform DSD PCM conversion a Path is simply set up with the DSD I/O Module as the input source and the PCM I/O Module as the output destination. The sampling rate of the Path is set to the required PCM rate and may be different on each Path.

By selecting the 'SRC' option in the DI Input Format Selection Menu, the input source for the DSD I/O Module can be internally routed from the DSD I/O Module outputs. This method of bridging the two ADA-8XR Paths results in a signal flow which has one set of input channels, but two sets of output channels, one on each Path.

A selection of Factory Stores have been created for various common applications of the DSD I/O Module. These are made available automatically when Default Stores are reloaded (Preferences menu) after installation of a DSD I/O Module. The latter three of those listed below are only available if an additional PCM-type digital I/O Module is fitted If no PCM-capable I/O Module is present only the non-PCM DSD Stores are made available.

Analogue to DSD / DSD to Analogue
Use this store for common A/D and D/A applications.

Path 1 is configured for analogue to DSD conversion, the DSD output format is SDIF 3 and the Path is synchronized to the wordclock input of the Utility Module (if detected, otherwise local sync).

Path 2 is configured for DSD to analogue conversion, the DSD input format is SDIF 3 and the Path is synchronized to the SDIF 3 inputs using automatic channel selection.

Analogue to DSD / DSD to Analogue (MAC-DSD Master)
Use this store when the ADA-8XR is to be the master in a MAC DSD / SuperMAC connection.

Path 1 is configured for analogue to DSD conversion, the DSD output appears on the MAC DSD interface and the Path is synchronized to the wordclock input of the Utility Module (if detected, otherwise local sync).

Path 2 is configured for DSD to analogue conversion, the DSD input format is MAC DSD and the Path is synchronized to the MAC DSD interface.

Analogue to DSD / DSD to Analogue (MAC DSD Slave)
Use this store when the ADA-8XR is to be the slave in a MAC DSD connection.

Path 1 is configured for analogue to DSD conversion, the DSD output appears on the MAC-DSD interface and the Path is synchronized to the MAC-DSD interface.

Path 2 is configured for DSD to analogue conversion, the DSD input format is MAC-DSD and the Path is synchronized to the MAC-DSD interface.

Analogue to DSD and PCM
Use this store when mastering for SACD and CD simultaneously (only available when a PCM module is fitted).

Path 1 is configured for analogue to DSD conversion, the DSD output format is SDIF-3 and the Path is synchronized to the wordclock input of the Utility Module (if detected, otherwise local sync).

Path 2 is configured for synchronous sample rate conversion, and the Path is synchronized to Path 1, with a modified rate of 44.1kHz. The output is routed to an additional PCM-type digital I/O Module (for example an AES 3 I/O Module) with 16 bit wordlength and SNS2 noise shaping.