Standard; Digital Inputs; Digital Input Capabilities; Digital Outputs - Apogee AD-8000 Operating Manual

Headroom requirements vary with the type of music, but can range from 8 dB for rock, to 24 dB for classi-
cal music. The first amplifier stage can accommodate this range with no compromise in the noise floor due to
careful design.
To further optimize the design, the attenuator has two settings, one for professional inputs and one for con-
sumer inputs.
Common Mode Rejection/RF Filtering
The first stage includes a common-mode and differential filter. The latter has a corner frequency of 265 kHz.
The common-mode filter is designed to reduce common-mode pick-up at RF frequencies, as well as to reduce
conducted and radiated RF emmissions in compliance with FCC and CE regulations. Each analog channel is
adjusted for maximum common mode rejection before leaving the factory.
Analog Line-Level Inputs
The default source for channels 1–8 are the line-level analog inputs. The default nominal level for these
inputs is +4 dBu (professional setting). DIP switch SW1 on the back allows this to be changed to –10 dBV (OFF
position—consumer setting.)
When the inputs are selected as analog source, the DIGITAL ROUTING matrix has the top row illuminated,
indicating that all eight channel sources are analog (the A/D converters), and the DIG IN 1/2, DIG IN 3/4, DIG
IN 5/6, and DIG IN 7/8 LEDs are all off. If any of these LEDs are on, they can be turned off by pressing the DIG-
ITAL IN mode button briefly and then the channel button, or alternatively, all the DIGITAL IN LEDs can be tog-
gled by holding down the mode button.

Standard

In the standard configuration, analog inputs are plugged into the XLR jacks on the rear panel. Optimum per-
formance is obtained by feeding a balanced pro or consumer level into the connector. The AD-8000 contains
dynamic input balancing circuitry, so an unbalanced signal can also be utilized, if desired. Levels can be trimmed
over a range of 20 dB by adjusting the trimpots through the small holes in the front panel.
The AD-8000 has facilities for accepting up to 8 digital inputs. Each pair of channels (1/2, 3/4, 5/6 and 7/8)
can be selected to accept either analog (A/D) or digital inputs.
There can be up to six different digital sources in the AD-8000 – AES and S/PDIF on-board inputs plus up
to four AMBus cards. At the time of writing, it is only possible to use one digital input at a time, but a future
firmware upgrade is intended to enable up to four digital input pairs to be selected simultaneously. You can
check the features of the latest firmware revision by visiting our Web site, http://www.apogeedigital.com/. The
source to be used is determined by the SOURCE selection under DIGITAL ROUTING. Pushing this switch tog-
gles the selection between the standard S/PDIF (IEC958) input connector (RCA), the standard AES input con-
nector (XLR), and up to four AMBus cards.
Having chosen the digital source, you can assign it to a pair of channels (1/2, 3/4, 5/6 or 7/8) by pressing
the CHANNEL SELECT button under either one of the channels in the pair to which you wish to assign this
source.
Digital sources are always enabled in channel pairs, by pushing the DIGITAL IN mode switch and one of the
channel buttons (either the odd or even numbered button will work). The DIG IN legend will illuminate.
The dot matrix display shows which channels have an analog source and which have a digital source. The
matrix also identifies the AMBus card slot being used as the source for each pair of digital outputs.

Digital Input Capabilities

Standard inputs on the AD-8000 are an AES/EBU input pair (a single XLR connector) and an S/PDIF (IEC 958)
input pair (one single RCA connector).
AD-8000 Operating Manual

Digital Inputs

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