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AES balanced and
unbalanced signals
When working with Digital audio it is not uncommon to face the problem that one piece of equipment has a
balanced AES output on an XLR or multi pin connector, the other has an unbalanced BNC or RCA/Phono
connector.

Some equipment with multiple AES inputs  and outputs will present these signals on 25 way 'D' connector like the
Yamaha YGDAI card range ( eg
Yamaha MY8AE ).

I faced this very problem building the Euroscreens O.B. vehicle. A 32x32 Nevion AES matrix was installed into the
truck, allowing all AES digital audio infrastructure to be easily interconnected.

The Snell Wilcox Em/De embedder IQMUX 42 cards feature BNC AES inputs and outputs with a characteristic input
and output impedance of 75 Ohms.


The audio desk a Yahama QL1 was fitted with a Yamaha YGDAI MY16AE  card providing 8 stereo ( or depending
on how you count, 16 mono ) AES
balanced inputs and outputs split over two 25 way D connectors which needed
to be connected to the AES matrix. Pin out as below ( pairs 1-4 translate to pairs 5-8 on the second connector )
Yamaha YGDAI AES Input and Output pinout on MY8AE and MY16AE card
I needed a method for connecting my Yamaha balanced inputs and outputs to my Nevion Matrix, the answer is
passive, requires no power, works either way ( Bal to Unbal or Bal to Un-bal ) and works extremely well.

The Upgrayde Broadcast AES 01 board.

We have three of these units mounted in our OB truck in a 1U box providing all interfacing between our
Yahama
audio desk,
Nevion, AES matrix and Ross 16 channel embedders. It works great.
The board has been designed to allow 4 units to be fitted to a single 1 U
chassis box providing full isolation of all signal inputs to outputs.

Technical specifications will be published in due course with Eye diagrams
over industry standard CAT  twisted pair cable and BNC cable. Results
suggest cable runs in excess of 100m are perfectly acceptable.

The board has been supplied with a header allowing easy connection and
wiring to XLR or other connectors.

The board has been manufactured in U.K. and is RoHS/Pb free.