R a d i o S y s t e m s , I n c .
D D A 1 X 8 S H M a n u a l
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P a g e 4
Overview
The Radio Systems DDA-1x8SH is a high-performance digital distribution amplifier
with input/output connectors that conform to the St RJ45 wiring standard.
The amplifier allows two independent inputs to be switched to the eight outputs by
depressing an A/B switch on the front panel.
Total isolation is provided between A/B input s and the eight outputs. Each
balanced channel is unaffected by the other channels. The Radio Systems DDA-
1x8SH Digital Distribution Amplifier allows digital audio sources to be routed to
multiple locations while maintaining the integrity of signal quality throughout.
Mounting
The DDA-1x8SH occupies only 1 rack unit (1-3/4 inch) of height in a 19 inch EIA
rack. To allow for adequate ventilation, avoid mounting the unit directly above
large heat producing equipment such as power amps or power supplies.
When stacking units, it is recommended that one rack space (1-3/4 inch) remain
open between every three units.
Operation
Apply an AES3 signal, sampled from 32 KHz to 96 KHz to either (or both) of the
unit’s inputs. The applied signal is distributed to each of the unit’s eight outputs at
unity gain.
Two different signals may be wired to the inputs; the signal routed to the
distributed outputs is determined by the position of the A/B input select switch on
the front panel.
LEDs on the front panel indicate which input (A or B) is selected, and whether audio
(data) is present.
Connections
The DDA-1x8SH conforms to the St wiring standard. On the RJ45, the
pinouts are as follows:
Pin1: AES +
Pin2: AES -
Ground is carried through the shield of the RJ45 cable. At the output connectors,
ground reference may be selected by installing shorting jumpers (included) on to
the headers adjacent to the RJ45 jacks. Jumping the center pin with ‘CH” will
reference the audio output ground to chassis ground; jumpering the center pin with
“IN” will reference the audio output ground to the input audio ground.
AC line voltage is user selectable from the lid of the cabinet by inserting a thin
shafted screw driver through the vent holes to move the red line voltage selector
switch to the left for 230V operation, and to the right for 110V operation (factory
default).
