Issue 4, October 2016
Model 760-03/77 User Guide
Page 10
Studio Technologies, Inc.
for Surround
maintain a common sample rate and tim-
ing reference. Having all signals “locked”
together helps to ensure proper handling
by the Model 760-03’s all-digital signal
control path.
There is, however, an exception worth not-
ing. Circuitry associated with stereo input
C has sample rate conversion (SRC) ca-
pability, allowing virtually any digital audio
signal to be connected. A signal connected
to stereo input C can have an independent
sample rate and timing reference and still
be monitored correctly. Refer to the Techni-
cal Notes section of this user guide for a
detailed review of the SRC capability.
The Model 760-03’s digital audio inputs
are intended for connection with balanced
digital audio sources that are compatible
with the AES3 standard. This signal type
has a nominal impedance of 110 ohms
and a nominal signal level of 5 Vpp.
One 25-pin female D-subminiature con-
nector (DB-25F) is used to interface with
the 16 channels associated with surround
input A, surround input B, stereo input A,
and stereo input B. Each of the eight physi-
cal connections supports two audio chan-
nels. Often a wiring assembly prepared for
these digital audio inputs would typically
be identical to that of a TASCAM®-type
(AES59-compliant) input assembly. An as-
sembly of this type would have eight 3-pin
female XLR connectors on one end and
a 25-pin male D-subminiature connector
(DB-25M) on the other. Refer to Figure 4
for details on connecting with the 25-pin
female D-subminiature connector.
On the Model 760-03 stereo input C uses
a 3-pin female XLR connector for interfac-
ing with a digital audio signal source. The
mating cable should have a 3-pin XLR
connector wired such that goes to
pin 2, the – signal to pin 3, and shield to
pin 1.
Unbalanced AES3 digital audio signals
can also be used with the Model 760-03’s
inputs if external coupling transformers
(“baluns”) are utilized. These impedance-
matching (75 ohms to 110 ohms) and level
step-up transformer assemblies typically
provide a BNC connector on their input
and a 3-pin male XLR connector on their
output.
Digital Monitor Outputs
The 25-pin female D-subminiature
connector labeled Digital Monitor Outputs
provides access to the Model 760-03’s
16 channels of digital audio monitor output:
pre-fader surround, post-fader surround,
post-fader stereo, and stereo input C
direct. The pre-fader surround digital
monitor output channels are intended
Signal
Signal
Connections
Channel High (+) Low (–) Shield
Surround Input A L/R
1
24
12
25
Surround Input A C/LFE 2
10
23
11
Surround Input A LS/RS 3
21
9
22
Stereo Input A
4
7
20
8
Surround Input B L/R
5
18
6
19
Surround Input B C/LFE 6
4
17
5
Surround Input B LS/RS 7
15
3
16
Stereo Input B
8
1
14
2
Notes:
1) All signals transformer-coupled digital audio;
balanced AES3 (110 ohms, 5 Vpp) compatible.
2) Connector type on Model 760-03 is 25-pin female
D-subminiature (DB-25F). Installer must provide male
(DB-25M). Connector uses 4-40 threaded inserts for
locking with mating plug.
3) Wiring scheme follows AES59-2012 convention.
Standard TASCAM-type wiring harnesses are directly
compatible, with the possible exception of 4-40 screw
threads being required.
Figure 4. Connections for Surround A,
Surround B, Stereo A, and Stereo B Digital Inputs
