8-channel I/O Board

  • 8 channels
  • Combined I/O board
  • DSP built-in
  • Output-signal re-quantizing to 16 or 20 bits with dithering and noise shaping
  • I/O sample-rate converter (option)

 data sheet (163 KB)

The XAF board provides 8 inputs and 8 outputs for the ADAT 8-channel format used, for example, by digital tape machines.
The inputs and outputs of the board can optionally be equipped with sample-rate converters and can therefore handle asynchronous signals. All converters can be disabled together using the control program.
The DSP is a standard feature allowing for audio corrections with high quality. For example, the input level can be adapted to the required recorder headroom, and phase inversion allows »reverse-polarity« signals already at the inputs of the audio network to be corrected.


Sample-rate converters for connecting asynchronous signals can be incorporated on request. Audio with rates between 40 and 50 kHz can be applied.
In addition, the board includes a quartz-controlled generator producing a 44.1-kHz or 48-kHz wordclock. Accuracy is better than 50 ppm.

Separate Synchronisation

The output signal can be synchronised to the input signal of the board as required independently of the system clock. The necessary sample-rate converters also make the signal available on the NEXUS audio network.

Noise Shaping and Dithering

The XAF board allows for outputting the 24-bit NEXUS audio signal to external downstream units with a 16-bit or 20-bit resolution. Inaccuracies emerging from truncation errors leading to deterioration of the S/N ratio and THD&N are minimized by re-quantizing using a dithering algorithm. In addition, a selectively engaged noise-shaping function moves the noise energy up to frequency ranges less perceivable to the human ear.
The noise reduction achieved in the range below 1 kHz is approximately 15 dB and about 10 dB in the critical range around 3 kHz. Noise shaping is computed on the integrated signal processor on the basis of a 5th-order algorithm.


The front panel of the board includes an LED indicating the status of the input signal.


XAF version w / o SRC
XAF-SRC version w / SRC (inputs and outputs)
A special XAF version supporting the 32-KHz sample rate can be supplied for ADAT-format digital audio signals.

XAF01 Specifications

Data formats ADAT
Audio data 24 Bit, 20 Bit, 16 bits
Sample rates 44,1 kHz, 48 kHz
32-KHz support optional
variable w / SRC
Inputs 8 channels, TOSLINK optical ports
Outputs 8 channels, TOSLINK optical ports
Features (per input) phase inversion, gain
Features (per output) transparent transmission of all ADAT-format user bits (with SRC disabled); noise shaping and dithering for 16- and 20-bit signals
Indicators PLL status (LED)
Gain adjustable input gain (±20 dB)
Propagation delay 4 samples; (0.7 ms when using SRC)