ULN-8 Users Guide
121
Using analog inserts on the ULN-8
The “Mic S/R” input mode creates pre-converter inserts on a per-channel basis by utilizing the
Mic input as the channel input and Line input as the insert return. For example, to insert a
compressor on Analog 1:
1. Set Analog 1’s input type to Mic S/R
2. Connect your signal (mic or line level) to Mic input 1
3. Connect Send 1 to your compressor’s input
4. Connect your compressor’s output to Line input 1
You have now inserted your compressor between the output of the mic preamp and the A/D converter.
You cannot route signal from a DAW channel to the balanced sends; to route signals from your computer
to the D/A converters, you must use the Line/Monitor outputs.
AES Digital Audio
The ULN-8 supports 8 channels of digital audio over copper-based connections. The native format of the
ULN-8 is AES, but can be converted to SPDIF or optical using third-party adapters. The ULN-8 operates
in single-wire mode, providing 8 channels of digital audio at all sample rates. The ULN-8’s digital I/O
connections are made using industry standard Tascam/Digidesign pinout DB25 cables.
Wiring details for this connector can be found in the
appendix.
Digital audio interface options can be greatly expanded through the addition of a
.
Clock Sync
Clock sync is a serious consideration in any digital audio system.
If you are recording analog sources with ULN-8, you can simply use the unit’s high-quality internal clock
source to drive the converters. This is the easiest case to deal with.
If you need to interface with other devices digitally or ensure sample accurate sync with video sources, the
extensive clock synchronization capabilities of ULN-8 will prove to be more reliable (and better sounding)
than much higher priced alternatives.
There are three different ways to get external clock information into the unit:
1. Sending a word clock signal into the WC Input BNC.
2. Sending an AES signal into the Digital input.
The BNC word clock input port is a 75 Ohm terminated coaxial input. It should be driven by a 75 Ohm
source driver and interconnected with 75 Ohm coaxial cable. If you do not use proper cabling and source
drive, you will introduce reflections on the word clock cable which will propagate jitter into the recovered
word clock.
The AES recommended procedure for distributing clock is to use an AES clock signal. The AES clock signal
is an AES digital audio signal with no audio activity. The LIO-8 only uses the AES preambles for clock
recovery, so it is immune to data dependent jitter effects. This means you can reliably use the Digital Input
as a clock source with or without audio data.
