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User's Guide
MADI Converter
6 x Bidirectional
MADI Optical to BNC Converter
6 coaxial Inputs and Outputs
6 optical Inputs and Outputs
1 to 3 MIDI Distributor
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Contents
1 Introduction ........................................................................................................3
2 Package Contents..............................................................................................3
3 Technical Specifications ...................................................................................3
3.1 Inputs..................................................................................................................3
3.2 Outputs ...............................................................................................................4
4 Operation ............................................................................................................4
5 Operation with MADI Bridge .............................................................................5
6 Inputs and Outputs
6.1 MADI Inputs........................................................................................................6
6.2 MADI Outputs .....................................................................................................6
6.3 MIDI Input and Outputs.......................................................................................6
7 Technical Background
7.1 MADI Basics .......................................................................................................7
7.2 MADI Converter Technology ..............................................................................8
8 Block Diagram....................................................................................................9
9 Warranty............................................................................................................10
10 Appendix...........................................................................................................10
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1. Introduction
The MADI Converter is a useful tool for any kind of MADI signal. The device converts MADI
digital audio streams from optical format to coaxial and from coaxial to optical. The compact 19"
device with 1 unit height contains six bi-directional converters, operating fully independently. All
12 inputs are equipped with status LEDs on the front panel.
All input signals will pass through absolutely unaltered. The MADI converter will operate with
any MADI format, be it 56-channel, 64-channel, any sample rate, even out-of-spec data rates
and violations of the MADI standard. Special equalisation and highly sensitive input stages allow distances of up to 100 meters using coaxial cables – even between multiple units.
Additionally, a MIDI distributor copies one MIDI input signal to three MIDI outputs, removing the
need for an external MIDI distributor.
The MADI converter is an ideal companion to RME's MADI Bridge. The Bridge's six coaxial
inputs and outputs can be converted to optical, a format which is advantageous in live and installed setups, and for longer cable lengths. The device can be placed underneath the MADI
Bridge ideally. The coaxial BNC inputs and outputs of the two devices will be right next to each
other vertically, and can be connected with short patch cables without cable crossing and cluttering.
2. Package Contents
Please check that your MADI Converter package contains each of the following:
• MADI Converter
• Manual
• Power chord
3. Technical Specifications
3.1 General
• Power supply: Internal switching PSU, 100 - 240 V AC, 20 Watt
• Typical power consumption: 6 Watt
• Dimensions including rack ears (WxHxD): 483 x 44 x 242 mm (19" x 1.73" x 9.5")
• Dimensions without rack ears/handles (WxHxD): 436 x 44 x 235 mm (17.2" x 1.73" x 9.3")
• Weight: 2 kg ( 4.4 lbs)
• Temperature range: +5° up to +50° Celsius (41° F up to 122°F)
• Relative humidity: < 75%, non condensing
3.2 Inputs
MADI
• Coaxial via BNC, 75 Ohm, according to AES10-1991
• High-sensitivity input stage (< 0.2 Vpp)
• Optical via FDDI duplex SC connector
• 62.5/125 and 50/125 compatible
• Accepts any MADI signal
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MIDI
• 1 x 16 channels MIDI
• 5-pin DIN jack
• Optocoupled, ground-free input
• Fixed MIDI Thru functionality
3.3 Outputs
MADI
• Coaxial via BNC, 75 Ohm, according to AES10-1991
• Output voltage 600 mVpp
• Cable length: more than 100 m
• Optical via FDDI duplex SC connector
• 62.5/125 and 50/125 compatible
• Fiber length: more than 500 m
MIDI
• 3 x 16 channels MIDI
• 5-pin DIN jacks
4. Operation
The user interface of the MADI Converter is characterized by a clearly structured architecture
and an unambiguous labelling of the front and rear sides.
The status of the 12 inputs is displayed by dedicated LEDs on the front panel.
The rear of the MADI Converter hosts six coxial BNC inputs and outputs, six optical inputs and
outputs, one MIDI input and 3 MIDI Thru outputs, all of them presented and labeled in a clear
and tidy way.
The specially developed internal high performance switching power supply allows operation of
the MADI converter with voltages ranging from 100 to 240 V AC. It is short-circuit-proof, has an
integrated line-filter, is fully regulated against voltage fluctuations, and suppresses mains interference.
Notes
• The INPUT LEDs of the MADI inputs are designed to light up with typical MADI signals. But
there is no real MADI detection and verification. Therefore, corrupt or non-standardized signals as well as high-frequency signals can cause the LEDs to turn on as well.
• The MIDI INPUT LED shows any MIDI activity, including MIDI Clock, MTC and Active Sens-
ing. The latter is sent by most keyboards every 0.3 seconds.
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5. Operation with MADI Bridge
The MADI converter is also an ideal
companion to RME's MADI Bridge.
The MADI Converter can convert the MADI
Bridge's six coaxial inputs and outputs to
optical, a format which is advantageous in live
and installed setups, and for longer cable
lengths. So in this combination, the MADI
Bridge effectively offers eight optical I/Os.
MADI Bridge and MADI Converter are
perfectly designed for each other. In case the
Bridge is placed above the Converter, the
coaxial BNC inputs and outputs of the two
devices will be right next to each other
vertically, and can be connected with short
patch cables. Thanks to interchanged inputs
and outputs, the cabling is done without
crossing and cluttering, maintaining perfect
overview.
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6. Inputs and Outputs
6.1 MADI Inputs
The rear of the MADI Converter has six coxial MADI inputs, available as BNC sockets. The
sockets are ground-free and seperated from ground by capacitive coupling. This method prevents ground loops and other distortions by potential differences between the connected units.
Note that the the transmission at the receiver still operates unbalanced.
The BNC input's ground-free design is built according to AES10-1991. The input's impedance is
75 Ohm. It will operate error-free from about 180 mVpp.
The two optical inputs use a FDDI (ISO/IEC 9413-3) compatible optical module each, according
to AES10-1991. More information can be found in chapter 7.1, MADI Basics.
6.2 MADI Outputs
The rear of the MADI Converter has six coxial MADI outputs, available as BNC sockets. The
BNC outputs are built according to AES10-1991. The output impedance is 75 Ohm. The output
voltage will be 600 mVpp when terminated with 75 Ohm.
The six optical outputs use a FDDI (ISO/IEC 9413-3) compatible optical module each, according to AES10-1991. More information can be found in chapter 10.1, MADI Basics.
6.3 MIDI Input and Output
The rear of the MADI Converter offers one MIDI input and three MIDI outputs via 5-pin DIN
jacks. All MIDI data at the MIDI input are passed on and copied to the outputs, a method known
as MIDI Thru function.
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7. Technical Background
7.1 MADI Basics
MADI, the serial Multichannel Audio Digital Interface, has been defined already in 1989 as an
extension of the existing AES3 standard following several manufacturers' wish. The format also
known as AES/EBU, a balanced bi-phase signal, is limited to two channels. Simply put, MADI
contains 28 of those AES/EBU signals in serial, i. e. after one another, and the sample rate can
still even vary by +/-12.5%. The limit which cannot be exceeded is a data rate of 100Mbit/s.
Because an exact sampling frequency is used in most cases, the 64 channel mode was introduced officially in 2001. It allows for a maximum sample rate of 48 kHz + ca. 1%, corresponding
to 32 channels at 96 kHz, without exceeding the maximum data rate of 100 Mbit/s. The effective
data rate of the port is 125 Mbit/s due to additional coding.
Older devices understand and generate only the 56 channel format. Newer devices often work
in the 64 channel format, but offer still no more than 56 audio channels. The rest is being eaten
up by control commands for mixer settings etc.. The ADI-648 and the HDSP MADI show that
this can be done in a much better way, with an invisible transmission of 16 MIDI channels and
the MADI signal still being 100% compatible.
For the transmission of the MADI signal, proved methods known from network technology were
applied. Most people know unbalanced (coaxial) cables with 75 Ohms BNC plugs, they are not
expensive and easy to get. The optical interface is much more interesting due to its complete
galvanic separation, but for many users it is a mystery, because very few have ever dealt with
huge cabinets full of professional network technology. Therefore here are some explanations
regarding 'MADI optical'.
• The cables used are standard in computer network technology. They are thus not at all
expensive, but unfortunately not available in every computer store.
• The cables have an internal fibre of only 50 or 62.5 µm diameter and a coating of 125 µm.
They are called network cables 62.5/125 or 50/125, the former mostly being blue and the
latter mostly being orange. Although in many cases not clearly labeled, these are always (!)
glass fibre cables. Plastic fibre cables (POF, plastic optical fibre) can not be manufactured
in such small diameters.
• The plugs used are also an industry standard and called SC. Please don't mix them up with
ST connectors, which look similar to BNC connectors and are being screwed. Plugs used in
the past (MIC/R) were unnecessarily big and are not being used any longer.
• The cables are available as a duplex variant (2 cables being glued together) or as a simplex
variant (1 cable). The ADI-648's opto module supports both variants.
• The transmission uses the multimode technique which supports cable lengths of up to almost 2 km. Single mode allows for much longer distances, but it uses a completely different
fibre (8 µm). By the way, due to the wave-length of the light being used (1300 nm), the optical signal is invisible to the human eye.
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7.2 MADI Converter Technology
A MADI patchbay basically can be realized in two ways: using a complete signal regeneration
(including reclocking), or by a buffered distribution of the un-processed input signal.
Complete Signal Regeneration: This method requires a complete MADI receiver per input,
and a complete MADI transmitter per output. The signal must be processed and reclocked. The
costs are extreme, as the special MADI chip (required 8 times!) is already very expensive. Additionally another very powerful FPGA is necessary. Operation gets clumbersome, as the unit has
to provide full clock support and control. The advantage is that the MADI signal at the output is
completely independent from the quality of the input signal, as it is fully newly generated.
Buffered Distribution: This method uses a sensitive receiver to amplify the input signal to a
standard level, then puts out this signal with an active driver stage. The signal is not processed
nor reclocked. The different combinations (routings) of the input and output signals as well as
the MIDI control can be performed by a fast FPGA. The component costs are dramatically lower
compared to the Signal Regeneration method. The operation is very easy, as the current clock
situation is completely ignored. The disadvantage is that the quality of the output signal depends on that of the input signal, as the signal is passed on nearly unchanged. Additionally the
maximum coaxial cable length is reduced, as a signal to/from the MADI Converter travels double the distance.
RME's MADI Converter uses adapted termination and a special equalizing, to reach higher
cable lengths despite its simpler design. The MADI Converter can even serve as cable buffer
for the limited outpus of some manufacturers (90 meter coaxial instead of 30 meter...).
Real world tests with MADI devices of various manufacturers confirmed the outstanding performance of the MADI Converter. There exists only one exception: The output signal of the
Sony 3348 (digital tape machine of the first MADI generation) becomes unreadable when
passed through the MADI Converter. This problem can be adressed by the MADI Bridge, which
offers a special 3384 compatibility mode (see manual).
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8. Block Diagram
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9. Warranty
Each individual MADI Converter undergoes comprehensive quality control and a complete test
at RME before shipping. The usage of high grade components allow us to offer a full two year
warranty. We accept a copy of the sales receipt as valid warranty legitimation.
If you suspect that your product is faulty, please contact your local retailer. The warranty does
not cover damage caused by improper installation or maltreatment - replacement or repair in
such cases can only be carried out at the owner’s expense.
RME does not accept claims for damages of any kind, especially consequential damage. Liability is limited to the value of the MADI Converter. The general terms of business drawn up by
Synthax Audio AG apply at all times.
10. Appendix
RME news, driver updates and further product information are available on our website:
http://www.rme-audio.com
Manufacturer:
IMM Elektronik GmbH, Leipziger Strasse 32, D-09648 Mittweida
Trademarks
All trademarks, registered or otherwise, are the property of their respective owners. RME and
Hammerfall are registered trademarks of RME Intelligent Audio Solutions.
Copyright © Matthias Carstens, 03/2006. Version 1.0
Although the contents of this User’s Guide have been thoroughly checked for errors, RME can not guarantee that it is
correct throughout. RME does not accept responsibility for any misleading or incorrect information within this guide.
Lending or copying any part of the guide or the RME Driver CD, or any commercial exploitation of these media without
express written permission from RME Intelligent Audio Solutions is prohibited. RME reserves the right to change specifications at any time without notice.
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CE / FCC Compliance Statements
CE
This device has been tested and found to comply with the EN55022 class B and EN50082-1
norms for digital devices, according to the European Council directive on counterpart laws in the
member states relating to electromagnetic compatibility (EMVG).
FCC
This device has been tested and found to comply with the requirements listed in FCC Regulations, part 15 for Class ‘B’ digital devices. Compliance with these requirements provides a reasonable level of assurance that your use of this product in a residential environment will not
result in harmful interference with other electronic devices.
This equipment generates radio frequencies and, if not installed and used according to the instructions in the User’s Guide may cause interference harmful to the operation of other electronic devices.
Compliance with FCC regulations does not guarantee that interference will not occur in all installations. If this product is found to be the source of interference, which can be determined by
turning the unit off and on again, please try to eliminate the problem by using one of the following measures:
• Relocate either this product or the device that is being affected by the interference
• Use power outlets on different branch circuits, or install AC line filters
• Contact your local retailer or any qualified radio and television engineer
FCC compliance statement: Tested to comply with FCC standards for home or office use.
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