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DIGITAL AUDIO
CONNECTIONS
Digital Connections
All digital inputs use nine-pin AMP MR
connectors. These connections input AES-3
(AES/EBU) compatible signals.
All digital outputs use six-pin AMP MR
connectors. These connections output AES-
3 (AES/EBU) compatible signals.
S/PDIF Signals
To connect a S/PDIF digital device to an
X-mixer digital input, use a 249 ohm resis-
tor to properly terminate the S/PDIF cable.
Install the resistor onto the connector per
the following illustration. Alternately, an
unbalanced-to-balanced line transformer
may be used.
Digital Connection Notes: AES/EBU out-
puts cannot connect directly to S/PDIF
inputs, a signal conversion interface must
be used. Some S/PDIF devices may not
work with the X-mixer's digital inputs,
even with the additional load resistor, due
to nonstandard signal levels or protocols in
the S/PDIF device.
Connecting SPDIF Devices
to X-mixer AES-3 Inputs
(impedance matching)
The S/PDIF output signal is lower than
the AES3 output signal but is sufficient
for the AES3 input. The resistor is used to
reduce the 110 ohm input impedance of
the AES3 input to the 75 ohms of the
S/PDIF driver and cable. This circuit does
not provide the ground isolation of the
transformer converter circuit.
Connecting SPDIF Devices
to X-mixer AES-3 Inputs
(transformer isolation and
impedance matching)
The S/PDIF output signal is lower than
the AES3 output signal but is sufficient
for the AES3 input. The transformer is
used to match impedance between the 75
ohm S/PDIF output and 110 ohm AES3
input and to provide ground isolation.
Digital Audio Serial Interfaces
DESCRIPTION
Interface
Connector
Impedance
Output Level
Max Output
Max Current
Min Input
Cable
Max Distance
TYPES OF DIGITAL AUDIO SERIAL INTERFACES:
interfaces are in wide use today (1) AES3 (formerly AES/EBU) and (2) S/PDIF. The AES3 format has
two varieties (AES3 & AES3id) designed for different cables and maximum cable lengths. The
S/PDIF format is designed for short cable lengths and inexpensive cables. The differences between the
standards is outlined in the chart above.
AES3 & S/PDIF COMPATIBILITY:
themselves are the same but the data in the packets are different between the two formats. An identifi-
er bit tells the decoder whether the stream is AES3 or S/PDIF. Because of this identifier bit, you can
not always convert between AES3 and S/PDIF with a signal conversion interface.
Signal
Shield
249 ohm
resistor
Signal
1 : 1.21
75
110
8
T H E
X - M I X E R
AES3
AES3id
Balanced
Unbal
XLR-3
BNC
110 ohm
75 ohm
2-7 Vpp
1.0 Vpp
7 Vpp
1.2 Vpp
64 mA
1.6 mA
0.2 V
0.32 V
twisted pair
Coax
100 m
1000 m
AES3 and S/PDIF are not the same. The data formats
Digital Inputs 13 - 14
balanced, AES-3 compliant
(9-pin connector signals)
Pin
Signal Description
1
High (+), digital input
2
Low (-), digital input
3
not assigned
4
not assigned
5
Audio & Logic ground
6
Shield Ground
7
Source Start output logic
8
Source Stop output logic
9
Channel On-off control logic
Digital Inputs 13 - 14
balanced, AES-3 compliant
(9-pin connector signals)
Shield
Pin
Signal Description
1
High (+), digital input
2
Low (-), digital input
3
not assigned
4
not assigned
5
Audio & Logic ground
6
Shield Ground
7
Source Start output logic
8
Source Stop output logic
9
Channel On-off control logic
D I G I T A L
C O N S O L E
S/PDIF
Unbal
RCA
75 ohm
0.5 Vpp
0.6 Vpp
8 mA
0.2 V
Coax
10 m
Two types of digital audio serial
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