AD122-96 MX
Operations Manual
10
Hardware Interconnections
Analog inputs are applied to the XLR connectors marked as LEFT ANALOG INPUT and RIGHT
ANALOG INPUT. The input signals can be balanced or unbalanced. The converter power line signal
rejection is very high (120dB common mode rejection) but use of high quality shielded audio cables is
recommended.
The XLR pin polarity is: Pin 2 non-inverting and Pin 3 inverting with +POLARITY setting.
The digital output AES/EBU connector (XLR) provides transformer coupled output for both AES/EBU
and consumer formats. A simple XLR to RCA adapter or adapter cable can be used to feed a coaxial
SPDIF input.
SYNC\WC INPUT (XLR connector) is used for external synchronization to digital audio or to a word
clock synchronization source.
Do not connect external sync to both the SYNC IN XLR and BNC Word
Clock input at the same time.
The four BNC connectors provide channel one and channel two data, word clock out, and word clock
in. They can be used for synchronizing additional converters to each other or an external TTL word
clock. The Word Clock Input is NOT internally terminated.
Regarding Termination:
For simple systems where there is only one device feeding the AD122-96MX’s Word Clock Input with
a short BNC cable, termination is probably not necessary. If you encounter problems getting the
AD122-96MX to lock properly, or there are other devices in the “chain;” termination may be
necessary.
If the AD122-96MX is the only unit being fed the Word Clock signal, connect the cable using a BNC
"T" adapter plugged into the “Word Clock Input.” On the other side of the “T”, place a 75 Ohm BNC
terminator connector. If the Word Clock is chained to other devices using “T” connectors, be sure that
there is a 75 Ohm terminator on the “T” of the LAST device in the chain and that none of the other
devices have INTERNAL TERMINATION. Alternately, if there is only ONE device with internal
termination, it can be wired at the “end of the chain” in place of the terminator. The important point is
that there is only ONE termination and it is located at the end of the chain.
The same approach may be used to chain the Word Clock output of the AD122-96MX. In this case,
there is no “T” on the AD122-96MX Word Clock Output. As described above, the “T” adapters should
be placed on the Word Clock input of the devices the AD122-96MX is feeding, with the termination
ONLY at the very end of the chain.
Maintenance
The
Model AD122-96 MX
is an auto calibrating converter requiring no periodic adjustments. The unit
generates a significant amount of heat (25 watts maximum). The temperature rise is no cause for
concern, but allowing for some airflow is always a benefit from a long-term reliability standpoint. It is
especially important not to block the openings in the top cover of the unit.
The front panel is gold plated (24 karat gold). Use a soft cloth (and plain water, if necessary) to clean
fingerprints.
