Appsys ProAudio ADX-32A User manual

Application Systems www.appsys.ch
ADAT Multicore Extender
ADX-32A / ADX-64A-PRO
User's Manual

Contents
1. Device overview.....................................................................................................................3
1.1. Front panel.....................................................................................................................3
1.2. Rear panel......................................................................................................................3
2. Typical application..................................................................................................................4
2.1. Digital snake (32 channels)..............................................................................................4
3. Important sa ety notes............................................................................................................5
3.1. Cat5 connections............................................................................................................5
4. Introduction...........................................................................................................................5
4.1. Overview.......................................................................................................................5
4.2. Applications...................................................................................................................5
5. Theory o operation................................................................................................................6
5.1. Optical transmission........................................................................................................6
5.2. Electrical transmission.....................................................................................................6
5.3. Latency..........................................................................................................................7
5.4. Jitter.............................................................................................................................7
6. Front panel connections..........................................................................................................8
6.1. Cat5 Connection 1..........................................................................................................8
6.2. Cat5 Connection 2 (ADX-64A-PRO only)...........................................................................8
7. Rear panel connections...........................................................................................................9
7.1. Power Input....................................................................................................................9
7.2. ADAT 1-4......................................................................................................................9
7.3. ADAT 5-8/Wordclock (ADX-64A-PRO only) .......................................................................9
8. Settings..............................................................................................................................10
8.1. Cat5 Termination..........................................................................................................10
8.2. Transmission direction (ADAT 1-4)..................................................................................10
8.3. Transmission direction (ADAT 5-8), ADX-64A-PRO only....................................................11
8.4. Channel 5 mode selection (ADAT or Wordclock)...............................................................11
8.5. Wordclock termination...................................................................................................11
9. Wordclock synchronization....................................................................................................13
9.1. General concept............................................................................................................13
9.2. Wordclock synchronization over ADAT............................................................................13
9.3. Wordclock synchronization over coaxial cable...................................................................13
10. Example applications...........................................................................................................14
10.1. Digital 16/16 multicore................................................................................................14
10.2. Digital 24/8 multicore (Wordclock-Sync over ADAT)........................................................15
10.3. Digital 40/16 multicore (Wordclock-Sync over dedicated coaxial cable)..............................16
11. Settings overview...............................................................................................................17
12. Speci ications....................................................................................................................18
13. Warranty...........................................................................................................................20
13.1. Terms and conditions...................................................................................................20
13.2. Contact......................................................................................................................20
13.3. About this document...................................................................................................20

1. Device overview
1.1. Front panel
The connectors “Cat5 Connection 2“ are only available in the 64 channel version (ADX-64A-PRO).
1.2. Rear panel
The connectors „ADAT 5-8/WC“ are only available in the 64 channel version (ADX-64A-PRO).

User's Manual
2. Typical application
2.1. Digital snake (32 channels)
The diagram below shows a typical application o the ADAT Multicore Extender: One Cat5 cable is
used or both the transmission o 24 channels rom the stage to the mix console, and 8 channels in the
opposite direction. All 32 channels are also ed into a monitor console and into a multitrack recorder.
Other examples setups can be ound in chapter 10. Example applications.
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ADX-32A / ADX-64A-PRO
3. Important sa ety notes
3.1. Cat5 connections
Use the Cat5 cable ONLY between ADAT Multicore Extenders!
NEVER connect an ADAT-Multicore Extender to any Ethernet networking device (PC,
Switch, other network equipment)! The ADAT Multicore Extender and/or the network-
ing device may be DAMAGED!
4. Introduction
4.1. Overview
The ADAT-Multicore Extender devices are designed or building an inexpensive digital multicore
system, which acts, together with ADAT compatible mixers and converters, as an ideal
replacement or traditional analog multicores. The bene its are:
Heavily reduced cabling: one single Cat5 cable replaces 32 analog cables
No noise, hum, crackling etc. thanks to digital transmission and galvanic isolation
Very low latency (<0.6µs over 100 t Cat5 cable)
Simple, reliable and robust design
Scalable: available in 32 or 64 channel versions,
the 32 channel version can be easily upgraded to a 64 channel system
Wordclock distribution option (no coaxial cable needed) with the ADX-64A-PRO
Local loopback unction provides ADAT pass-through on the same device. This allows the
connection o additional monitoring equipment or can be used as wordclock source
Compatible with all data ormats using TOSLINK optical connectors:
ADAT Optical („ADAT Lightpipe“) 24bit/48kHz, ADAT S/MUX (Double Speed/DS, 24bit/96kHz),
ADAT S/MUX4 (Quad Speed/QS, 24bit/192kHz), SPDIF, AC-3, DTS etc.
Ruggedized 19“ aluminium rack case
Quality product „Made in Switzerland“
4.2. Applications
Using the ADX-32A, 4 ADAT Lightpipe-connections (32 channels o audio) can be transmitted
over a single Cat5 cable, up to a maximum distance o 330 t (100m).
Using the ADX-64A-PRO, 8 ADAT-Lightpipe connections (64 channels o audio) can be
transmitted over two Cat5 cables. This device also supports the transmission o a dedicated
wordclock signal (BNC connectors) along with the ADAT streams. When using this option, the
number o ADAT connections is reduced to 7 (56 channels o audio).
Both devices are designed or maximum lexibility: The direction o data transmission can be
selected individually or each ADAT connection. Thus, the ADX-32A can be operated in 32/0,
24/8, 16/16, 8/24 or 0/32 TX/RX channel con iguration, and the ADX-64A-PRO can be
con igured to 64/0, 56/8, 48/16 etc. to 0/64 o TX/RX channels.
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User's Manual
For audio distribution to several places, up to 32 ADAT Multicore Extenders can be daisy-chained
together. This eature can be used or complex setups, e.g. multiroom audio distribution or the
connection o additional monitoring equipment. Each ADAT stream can be ed into the Cat5 at
an arbitrary place and is then distributed to all other connected devices.
All ADAT connections work completely independent o each other. This makes it possible to
transmit di erent data ormats, sample rates, resolutions etc. at the same time over the same
Cat5 cable. This allows not only the ADAT protocol extensions S/MUX (DS/Double speed,
24bit/96kHz over 2 optical cables) and S/MUX4 (QS/Quad Speed, 24bit/192kHz over 4 optical
connections) but also many other encodings (S/PDIF, AES/EBU, AC-3) to be transmitted.
5. Theory o operation
5.1. Optical transmission
The commonly used ADAT Lightpipe inter ace (actually called “ADAT Optical“) uses Plastic
Optical Fiber (“POF“) as transmission media. POFs are very cheap and immune to
electromagnetic inter erence, but are limited to approx. 16 t (5m) transmission distance. Larger
distances cause problems as the light pulses are attenuated too much, leading to data errors
which usually result in drop-outs or crackles. Furthermore, POFs are also very sensitive to breaks
and sharp bends which may be a problem in harsh stage environments.
5.2. Electrical transmission
Electrical transmission over twisted pair cabling (e.g. Cat5) allows much longer distances than
POFs. Especially Cat5 cables are, as Ethernet cables, commonly used and very economic (many
buildings have Cat5 cables laid out already). Also, bending is not a problem, and or harsh
environments (like stage use), there is a selection o specially designed cable assemblies and
cable reels available, o ten using ruggedized Neutrik EtherCon® connectors.
Cat5 cable consists o our twisted pairs, each made up o two single wires. One pair can carry
one ADAT stream (8 channels), yielding a total transmission capacity o 32 channels.
The transmission method used on the Cat5 media is called “di erential pair signalling” or
“balanced transmission”. This means that each signal is transmitted over a wire pair, where one
wire carries the inverted signal o the other one. In contrast to unbalanced (ground-re erenced)
systems, di erential signalling provides very good noise immunity, because coupled noise a ects
both wires the same way and can be eliminated at the receiver's side by simply taking the
di erence out. Additionally, EMI is greatly reduced because the electric and magnetic ields
surrounding the two wires cancel each other out.
The technology used in the ADAT Multicore Extender (RS-485) has been used or a long time,
e.g. or lighting applications (DMX) or harsh industrial environments (Pro ibus). The commonly
used AES/EBU standard works in a similar manner, but is, due to its relatively low data rate, only
able to transmit two audio channels over one pair. State-o -the-art technology is used in the
ADAT Multicore Extenders to ensure reliable operation at the higher data rates required by the
ADAT protocol.
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ADX-32A / ADX-64A-PRO
5.3. Latency
Latency has – in contrast to traditional analog systems - always been a topic in digital audio
technology. High latency can lead to unwanted e ects, such as phasing, hall, echo etc. and can
seriously a ect audio per ormance. One design goal o the ADAT Multicore Extender was to
build a system o ering one o the lowest latency values on the market. By design, other digital
snake solutions (e.g. Ethernet based systems) have a relatively high propagation delay, because
audio data has to be sampled, bu ered, converted, transmitted, bu ered and then inally
converted back to the original ormat. In contrast, ADAT Multicore Extender uses only minimal
bu ering with no data conversion at all, achieving an excellent overall latency o less then 1µs.
5.4. Jitter
In any digital audio transmission, the clock signal picks up a certain amount o jitter (clock phase
noise). One must di erentiate between two kinds o jitter (actually, two e ects the jitter has on
an audio signal), as described below:
On one hand, there's the so called “sampling jitter”, occurring only at the point o digital-to-
analog conversion or vice versa. Sampling jitter can cause distortion or noise since the time-
domain in ormation o a signal is altered. Today, DACs and ADCs make use o various advanced
re-clocking technologies in order to attenuate the jitter. Well designed equipment is no more
sensitive to sampling jitter regarding audio quality.
On the other hand, when jitter occurs on an inter ace used or the transmission o the data (e.g.
when used with an ADAT inter ace), it's called “inter ace jitter”. This kind is much less critical
since it only has an audible e ect i its value is so large that it prevents the proper detection o
bits within the data stream ( or AES/EBU, the speci ication allows a jitter value o ±20ns, which
is about 25% o a bit time). In a properly designed system, such high values should never occur.
To cope with jitter, other systems use o ten special re-clocking circuitry (Phase Locked Loop,
“PLL”). A PLL has good jitter attenuation characteristics, but must be specially adapted to the
used data ormat and sample rate in order to achieve optimal results. ADAT Multicore Extender
uses another approach: Instead o transmitting a signal with a relatively large gain o jitter and
then attenuating it with a PLL, it makes use o the most advanced transceiver technology
available, which has a very good out-o -the box jitter per ormance. The overall jitter o an ADAT
signal transmitted over 330 t (100m) Cat5 cable is only 4ns (typ.) which ensures correct bit
detection with an appropriate sa ety margin. This approach provides some advantages:
Very low latency since no bu ering is required
Optimal transmission o arbitrary signals, independently o the encoding or speed
(e.g. ADAT, S/PDIF, AES/EBU, AC-3)
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User's Manual
6. Front panel connections
6.1. Cat5 Connection 1
Cat5 cable carrying ADAT connections 1-4. Jacks “A” and “B” are electrically paralleled.
Depending on the number o jacks used, the push button “Termination” has to be set:
1 cable = “ON”, 2 cables = “OFF”. See also 8.1. Cat5 Termination.
NOTE: Redundant connections (the connection o two units with two cables over A and B at the
same time) are not supported! This would lead to signal loops causing unde ined current low.
6.2. Cat5 Connection 2 (ADX-64A-PRO only)
Cat5 cable carrying ADAT connections 5-8 and the wordclock signal. Jacks “A” and “B” are
electrically paralleled. Depending on the number o jacks used, the push button “Termination”
has to be set: 1 cable = “ON”, 2 cables = “OFF”. See also 8.1. Cat5 Termination .
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ADX-32A / ADX-64A-PRO
7. Rear panel connections
7.1. Power Input
Power supply o the device. Use only the supplied DC adapter or a replacement with the
indicated voltage, power, polarity and matching connector (see 12. Speci ications). The input
has a reverse-polarity protection. I the Power LED does not go on when a DC adapter is
connected, check the polarity (inner positive).
The second module in the 64 channel version is internally supplied with power.
7.2. ADAT 1-4
ADAT Lightpipe inputs and outputs 1-4. The direction (TX or RX) must be set using the DIP
switches, see 8.2. Transmission direction (ADAT 1-4).
7.3. ADAT 5-8/Wordclock (ADX-64A-PRO only)
ADAT Lightpipe Inputs/Outputs 5-8 and wordclock Input/Output. The direction (TX or RX) must
be set using the DIP switches, see 8.2. Transmission direction (ADAT 1-4).
Channel 5 can either be used as ADAT or as wordclock transmission, see 8.4. Channel 5 mode
selection (ADAT or Wordclock).
ADATs 5-8 may also be used to build a simple ADAT splitter. To do this, connect “Cat5
connection 1” to “Cat5 connection 2” using a short Cat5 cable
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User's Manual
8. Settings
An overview o all switch settings can be ound in 11. Settings overview.
8.1. Cat5 Termination
For proper operation, the termination (push button on the ront panel) has to be set correctly.
The required setting depends on the position o the ADAT Multicore Extender within the cable
snake:
At devices on the end o a Cat5 snake (all devices having only one cable plugged in either A or
B), the termination has to be switched ON.
At devices in the middle o a Cat5 snake (all devices where cables are plugged into both jacks A
and B), the termination has to be switched OFF.
I you use only two devices (point-to-point connection), the termination must always remain
switched on.
Wrong termination settings are, depending on the cable length, not always noticeable
(the system appears to unction properly). But reliability and immunity to noise is sig-
ni icantly decreased, because signals re lections can occur (with missing termination)
or the transmitters get overloaded (with too many terminations).
Please ensure there ore that the termination settings are correct under any circum-
stances.
I you're using the system in the same setup all time, you may use scotch tape to ix
the push button (or remove the push button cap) in order to prevent unwanted opera-
tion.
8.2. Transmission direction (ADAT 1-4)
The transmission direction (input or output) or ADAT connections 1-4 is set by the DIP-switches
1-4.
Input (DIP switch in lower position = OFF): The ADAT connection is con igured as input (the
receiver is active). The received data is sent over the Cat5 cable.
The input signal is passed-through to the output alongside ("local loopback"). You can
use this output to connect additional monitors or as wordclock source, as shown in
9.2. Wordclock synchronization over ADAT.
10