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Description
The MLA-XLR is designed to act as a single channel, bi-
directional, long distance amplifier or driver for MIDI signals.
While the normal MIDI protocol specifies a maximum cable
distance of about 50 feet, this is sometimes not sufficient for some
installations. The reason for this restriction is based on simple
physics. MIDI uses a simple electrical interface known as a
current loop. This lends itself to immunity from noise and ground
loops while allowing for cost effective implementation.
Although successful installations of 100 feet or more have been
made, this is usually the exception rather that the rule.
Additionally, this requires high quality, shielded, low capacitance
cable. Much more than 100 feet of MIDI transmission requires
some buffering or amplification.
The MLA-XLR takes a MIDI input and converts it to a balanced,
differential signal using the RS-422 specification. At the other
end, another MLA-XLR detects the signal using a sensitive
receiver that has a high degree of noise immunity. Connecting the
two MLA-XLRs are two standard, shielded, twisted pair
microphone cables.
The combination of a low impedance, differential driver coupled
with a sensitive differential receiver signal lends itself to long
distance, error free installations required in professional
applications. It is now possible to send your MIDI signal through
1000 feet of cable or more. Using lower gauge, high quality, low
capacitance, shielded, twisted pair cables, it is possible to reach
distances of 4000 feet!
Since the MIDI signal is converted into a non-MIDI signal, an
installation requires a MIDI Line Amplifier at each side. The
MLA-XLR is compatible with the JLCooper MLA-1 and MLA10.
