• 24-bit, 192-kHz digital audio distribution
• Reclocking distribution
• Four AES router inputs
• Two AES router output bit-streams
• Ten digital audio outputs (five per AES stream)
• AES or S/PDIF outputs
• 75 Ω or 110 Ω (jumper selected) digital audio output impedance
• Transformer coupled digital I/O
• LED audio level meter
• Power presence LEDs (-15. +15, +3.3, and +5V)
• Front edge test points
• 240 mA quiescent draw @ ±15 V, 265 mA peak
• Fully compatible with all System 1000 card frames
• Module shown with RF component shield cover removed

The DDA-205 is a 10-output (dual 1x5 or single 1x10) AES digital audio distribution amplifier. Each digital audio distribution amplifier (DA) carries two audio channels (for a total of 4 equivalent analog audio channels). The card operates at sample rates between 32 and 192 kHz, at any word length up to (and including) 24 bits. The DDA-205 transparently passes all data bits, “channel status bits” (C), “validity bits” (V), and “user bits” (U) bits. The input-to-output delay is exactly one sample for data, C, V, and U bits.

The DDA-205 has an asynchronous 4x2 input router. The outputs from this router drive two digital audio distribution amplifiers.  The router is controlled from two 3-pin connectors on the rear of the System 1000™ card frame. Each digital distribution amplifier can be driven from any one of the four digital audio inputs. All four digital audio inputs may be asynchronous to each other. The distribution amplifiers will follow the sample rate of the selected input. The router can be used to configure the DDA-205 as a 1x10 digital DA. The two amplifiers sections may simultaneously be operated at different sample rates, word lengths, and data formats.

The DDA-205 has ten transformer-isolated AES digital audio outputs that are individually configurable for 75 or 110 Ω operation. This gives the user the ability to drive any combination of 75 and 110 Ω loads.

The DDA-205 has four 9-segment LED meters for monitoring the audio levels on each of the four audio output channels (four audio channels on two AES signals). These meters have a 3-position toggle switch that controls both the meter scale and peak hold functions. When the switch is down, the meters have a 48-dB range with 6-dB steps.  In the center position, the meters have a 20-dB range with 1-dB steps. In the up position, the meters have a peak-hold function, a 20-db range, and 1-dB steps. The meters are driven digitally and have very accurate thresholds. The response time is fast enough to capture all single-sample events, and LEDs remain illuminated long enough for these events to be observed by the human eye.

Each of the two output amplifiers has a 4-segment LED status display. This display indicates the sample rate of the digital audio signal, and alerts the user when an input signal is absent or contains errors.

The DDA-205 card is powered from the System 1000™ +15 and -15-volt supply rails. The 3.3 and 5-volt supplies are local to the DDA-205 card. The 5-volt supply is derived from the +/- 15-volt supply rails using an isolated DC-to-DC converter. The 3.3-volt supply is derived from the 5-volt supply using a linear regulator. This configuration provides a high-efficiency solution that is compatible with the System1000™ analog audio supply rails.

The DDA-205 may be inserted or removed from the System1000™ cardframe at any time. Reset and soft-start circuits monitor the status of the +/- 15-volt inputs, and the local +5 and +3.3-volt supplies. Digital audio outputs are available within 500 milliseconds after inserting the card. All System1000™ digital cards are designed to provide near-instantaneous operation when hot-plugged.

The DDA-205 will generate audio "black" when no input signal is present. This feature can minimize the probability of “pop” and “cracks” when a digital audio feed is momentarily interrupted. This feature also allows the DDA-205 to operate as a master clock generator. The sample rate of the digital audio black is jumper selected. The factory default is 48-kHz.

The DDA-205 is compatible with all Benchmark System 1000™ card frames and happily coexists with any combination of analog and digital modules.

The price of the DDA-205 is $875. Call our sales department at 1-800-262-4675 for availability.

Product Manual

Block Diagram