LavryBlue 4496
Operation
5
M•AD-824 Analog to Digital Converter
A.) M
•
AD-824 OPERATION
The M•AD-824 is a two-channel unit, converting analog audio to AES digital output in wordlengths of 16,
20, or 24 bits. It receives its clock (internal or external) from the M•SYNC board (multi channel sync). All
M•AD-824 units in a 4496 frame receive the same clock signal from the M•SYNC to minimize jitter and
inter-channel timing differences.
Looking at the back of the 4496, each M•AD-824 module has a group of three XLR connectors. In each
group, the LEFT INPUT is the
right
female XLR and the RIGHT INPUT is the
left
female XLR
connector. The male XLR is the AES digital output.
This “mirror image” position of the analog inputs is due to the straight-through construction of the
modules. Facing the front of the 4496, the Left channel is on the LEFT and the Right channel is on the
RIGHT side of each module’s PC board. The analog inputs are electronically ba4dBu nominal
level, configured by internal DIP switch for Pin 2 “+” (non-inverting) operation.
The output of the M•AD-824 is AES digital format, which is a 110 ohm balanced 5V standard. The output
is compatible with SPDIF format (75 ohm unbalanced), and can be made compatible by using a simple
adapter cable or “barrel” adapter from RCA to XLR. In some cases with older SPDIF I/O, it may be
necessary to use a transformer or simple electronic “level shifting” interface designed for this purpose, but
this is not typically the case. Because the M•AD-824’s AES output is transformer coupled, the signal
conductors MUST connect to pin 2 and pin 3 of the XLR connector. It is also OK to connect either Pin 3 or
Pin 2 to Pin 1 (but not
both
) in the XLR connector that plugs into the AES output.
Interface Standard/ Connector type
Signal -
Shield
AES XLR
Pin 2*
Pin 3*
Pin 1
SPDIF RCA
Center Pin
Outer Contact
Outer Contact
*Please Note: Because the AES/SPDIF signal is “polarity independent,” Pin 2 and Pin 3 can be
interchanged in the wiring scheme.
All analog audio and digital audio connections to the M•AD-824 are made with the three XLR connecters
on the back panel. There are no connections internal to the 4496 for these signals.
