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Figure 10: Analog input panel wiring

Symmetrical (balanced) shielded cables are highly recommended as balanced signals are less sensitive to AC

hum and radio interference. Unbalanced lines may result in noise especially over long cable runs.

6.4.3 AES/EBU digital audio cabling

Both AES/EBU XLR connectors on the LA8 are transformer balanced and wired according to IEC 268.

The 3-point female XLR input connector (IN) is provided for the amplifier to receive one AES/EBU (AES3) or coaxial

S/PDIF (IEC 60958 Type II) signal.

In order to set a daisy-chain layout, the 3-point male XLR connector (LINK) can be used to feed the input signals to the

next unit in the signal chain (see Figure 11). The LINK connector is electronically buffered to allow daisy-chaining any

number of amplified controllers. It also features a failsafe relay to ensure wiring continuity in case of amplified controller

shutdown (see Figure 12).

Here are important information about

cables for AES/EBU digital audio

• The quality required for the XLR cables will depend on the cable length and the signal sampling

frequency. As a starting point, a standard balanced microphone cable of maximum length of 50 m/150

ft can be used to transport a signal of maximum sampling frequency of 48 kHz. Higher sampling

frequencies may require reducing the cable length since the signal attenuation in cables increases with

the sampling frequency.

• As AES/EBU certified cables provide smaller attenuation/length ratio, it is highly recommended to use

them in installations requiring long cable runs or high sampling frequency signals. When using an audio

digital source at 48 kHz, the maximum length for AES/EBU certified cables is 300 m/1000 ft (typical).

• It is recommended to use single cuts of cable. Using several pieces will reduce performances.

• In case an amplified controller shutdowns, the failsafe relay makes a passive connection between the

AES/EBU IN port and the LINK port to maintain continuity. However the signal is no longer refreshed

for the next amplified controller, so that the input cable and the link cable must be considered as a

unique input cable with regard to the maximum supported length.

• In case of transmission losses, try to reduce the sampling frequency of the digital audio source.

Moreover, as a general rule, avoid using sources rated beyond 96 kHz as the maximum possible cable

length will be reduced while the additional information will anyway be cancelled by SRC to 96 kHz.

When using a digital source with S/PDIF format, the maximum cable length is 5 m/15 ft (typical).

IMPORTANT