The high-density input card for stereo line signals up to +15 dBU

HXAD NEXUS cards offer eight analog stereo line inputs (16 audio channels). Versions with D-Sub or RJ45 connectors are available, which are particularly suitable for applications that require small sizes with high audio quality at the same time.

The HXAD board is the best way to feed larger amounts of stereo signals into a NEXUS system when space is limited. The 24-bit A/D converter can digitize 16 signals with typical line levels. This analog input board also features Stage Tec's innovative circuit design with minimal converter errors and transformer isolated input stages. The dynamic range of 112 db (A) and the extremely low distortion factor of only 0.001% at 15 dBu allow a faithful reproduction of any typical analog signal. The unbeatable amplitude frequency response of +/-0.05 dB at 20 Hz - 20 kHz and the high aliasing suppression underline the outstanding quality known from Stage Tec products. With its galvanic isolation in pairs, the high-density input board allows efficient, high-quality connection of stereophonic sources to a NEXUS network.

To keep the packing density in systems as high as possible, this 16-channel card is only available with D-sub or RJ45 connections in 4 HP width. The use of cards with RJ45 sockets makes it possible, especially in fixed installations, to have common CAT5 cables laid as an inexpensive alternative to expensive, shielded audio cables. Stage Tec's extraordinary inputs ensure that the signal quality does not suffer as a result.

"Stereo version" of the outstanding XAD+ converter card

With a dynamic range of 112 dB and a maximum input level of 15 dBU, this NEXUS board is a space-saving replacement for XAD+ when it comes to stereophonic signals.

High-density card with 16 audio channels for large numbers of inputs in confined spaces

This board offers high channel density, meeting a high demand for required inputs, especially in situations requiring portability or low weight.

Version with transformers in each input channel even with high channel density

Despite the compact circuit design, each channel is transformer isolated. The input pairs (1/2, 3/4, etc.) share a common ground potential, since the module is intended for the connection of stereo and multi-channel devices. Stage Tec's transformer-insulated inputs have significant advantages over conventional circuits: They are insensitive to magnetic fields and have a lower distortion factor, especially at high and low levels and at low frequencies. They also offer high symmetry, galvanic isolation and a lower input capacitance.

Ground Lift" disconnectable ground connection

The connection to the common ground can be cancelled separately for each input pair (1/2, 3/4, etc.). This is done via DIP switches, which prevents the connection of the screen line to the internal analog ground.

Projects with high channel requirements in a small space

A 19" wide and 3U to 15U high NEXUS base unit is the intelligent binding that supplies the modules with the necessary voltage, the system clock of the CPU as well as audio and control data, monitors them and enables the user to operate them. A 3U level can accommodate up to twenty modules; in addition, the controlling XCPU card is located in one level. In addition to the three possible active levels, i.e. 3U, 6U or 9U, a base unit can contain up to two passive levels (each with a height of 3U), which can be filled with additional front panels of I/O boards to make full use of the space of the active levels. A good example of this is the XMIC+ card in the XLR version, whose inputs one to four are mounted directly on the PCB and whose remaining inputs five to eight are connected to a remote front panel connected with a Cat5 cable. In addition, all Stage Tec-NEXUS boards have a predetermined breaking point so that the front panels can be mounted independently of the actual slot, which means the overlapping of an 8HP wide front panel over the slot of another board whose separated front panel can be mounted on a passive plane. The connection is then made via a ribbon cable. A special case with particularly low weight is the 1U base unit, in which the cards are inserted transversely instead of lengthwise as usual and which contains active ventilation due to the insufficient convection cooling. With its high channel density and small footprint in the NEXUS base unit, HXAD is particularly appealing to users where every gram counts. Both in the OB van and in the mobile setup, the lightweight design of the basic units comes in handy. Added to this is the large number of channels on the HXAD board, with which many signals can be converted.

Tenders under high cost pressure

Tenders can often be tight with the budget, but you don't want to forego quality. The HXAD input board comes with 16 high-quality line level converters in just one board, which saves space in the NEXUS base unit and also the cost of a second input board. For an effective balance of space, price and channel capacity, the HXAD card, of course in the usual Stage Tec quality. The slim 4HP wide design with D-Sub or RJ45 jacks takes up little space, in contrast to the XAD+ board in XLR design which has eight times the width required to accommodate the same number of channels. The main difference to the XAD+ card is the common mass of the channel pairs and the double number of inputs.


Variant: D-Sub  1 x 4TE
D-Sub 25 Socked female 2x Line Level Input
Variant: RJ45 1 x 4TE
RJ45 4x Line Level Input

Technical specifications

Configuration, available separately for each channel

  Test-tone generation Phase inversion

A/D conversion

Type delta sigma converter
Resolution 24 Bit, 128-faches Oversampling

Audio data

Input level 15 dBu (max.)
Dielectric strength Signal wire—enclosure: < ±200 V (DC) (common-mode signal);
Signal wire—signal wire: < 20 V (AC) (dielectric strength RMS);
Shield—enclosure: < 48 V (DC)
Frequency response 20…20,000 Hz (–0.1 dB, +0.0 dB)
Input impedance > 10 kohm
Input Impedance CMR 120 dB@ < 100 Hz (typ.);
100 dB@1 kHz (typ.);
70 dB@15 kHz (typ.)
Gain –20…+20 dB, digitally adjustable
Distortion factor (THD+N) 0.001 %@15 dBu (typ.); < 0.002 %@1 kHz granted;
0.01 %@–15…+15 dBu (typ.);
< 0.02 % granted; < 0.3 %@–60 dBFS, 20…20,000 Hz
Dynamic range Dynamic range
Idle channel noise –109 dBFS (CCIR-RMS) (typ.)
Modulation noise –110 dBFS CCIR RMS (typ.) (noise@signal presence)
Crosstalk attenuation > 110 dB (@20…20.000 Hz)
HF resistance HF-demodulation resistant according to IRT standards (IRT-Pflichtenheft 3/5) and European standards
Sample rates NEXUS system clock (44.1/48/88.2/96 kHz)
Latency 0.33 dB@48 kHz (typ.)

Operation conditions

Temperature range 0 °C bis +50 °C
max humidity max. 90 %, non-condensing

Storage conditions

Temperature range –35 °C bis +70 °Cr
max humidity max. 90 %, non-condensing

Power supply

Voltage +4,9…5,2 V
Currrent 500 mA

Mechanical data

Weight 0,25 kg

NEXUS / NEXUS Star Technical specifications




HXAD Technical specifications