Glab LINE MIDI SWITCHER User manual

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Version 1.0
Table of contents
Structure __________________________________________________________ 3
Power supply ______________________________________________________ 5
Control Ground Lift (CTRL GND) switch ________________________________ 5
Working mode switches _____________________________________________ 6
Way of connecting __________________________________________________ 7
AB GND and ACD GND ground switches _______________________________ 9
MIDI functions_____________________________________________________ 10
Technical parameters ______________________________________________ 13
FCC Compliance___________________________________________________ 14
Declaration of Conformity___________________________________________ 15

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Dear Customer!
Thank you for choosing our product.
LINE MIDI SWITCHER (LMS-1) is a bidirectional, passive switcher of the audio signal
with galvanic separation between A, B, C, D outputs/inputs. The LMS-1 can be used as
amps switcher in “one of four” mode (guitar connected to an input of selected amp)
without occurring of the ground loops. The LMS-1 is controlled via MIDI interface and
buttons on the top of the device.
Basic features:
- working modes: 1) one IN input – four A,B,C,D outputs,
2) four A,B,C,D inputs – one OUT output,
- signalization of the power supply and connections state,
- four buttons for manual control,
- fully passive signal path (without active components and separating transformers)
assuring no influence of the switcher on the guitar sound
- switching based on the electro mechanic relays with silent switching system,
- ground connections optimization switchers,
- MIDI THRU connector,
- 9V DC power supply

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Structure
1 - output/input D 8 - output/input A
2 - ACD GND grounds switch 9 - input/output Y
3 - output/input C 10 - CTRL GND ground switch
4 - DS1 and DS2 – working mode switches 11 - 9V power supply connector
5 - MIDI channel settings switch 12 - MIDI IN input
6 - output/input B 13 - MIDI THRU output
7 - AB GND grounds’ switch

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14 - power supply indicator 19 - C output/input „ON” switch
15 - A output/input activity indicator 20 - C output/input activity indicator
16 - A output/input „ON” switch 21 - D output/input „ON” switch
17 - B output/input activity indicator 22 - D output/input activity indicator
18 - B output/input „ON” switch

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Power supply
LMS-1 should be supplied from 9V (DC) regulated source with capacity 100 mA or
more. Before plugging the power supply please check the pin polarization.
The device is protected against opposite polarity. If this protection switches on it is
needed to disconnect the power supply and wait few minutes before reactivation of the
device.
ATTENTION: Damages caused by improper power supply causes the loss of the
warranty.
Control Ground Lift (CTRL GND) switch
If the 9V power supply is fully separated (not connected with signal ground or
grounding) the CTRL GND switch should be set to ON position. If the 9V negative wire
is connected with other signal ground or grounding the Control Ground Lift switch
should be set to OFF.

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Working mode switches
The LMS-1 posses two working modes set by DS1 switch
- DS1=OFF, one input/four outputs, Y IN/ABCD OUT, this working mode
enables for example to choose the amp to which the guitar will be plugged in
- DS1=ON, four inputs/one output, ABCD IN/Y OUT, this working mode
enables to choose signal source (e.g. guitar) connected to the amp.
In working mode one input/four outputs the DS2 switch decides about working mode of
the switches:
- DS2=OFF, „one of four” mode, pressing of chosen switch makes a connection
between input Y and chosen output,
- DS2=ON, „one or more” mode, pressing of chosen switch toggles the state
(correspondingly turning on or off) of chosen output what enables to send the signal to
several devices. It is not recommended to use this mode for guitar with two or more
amps because it creates the ground loop which can (especially on high gain tones)
provoke audible hum in speakers.

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Way of connecting
Scheme No. 1 (on the inside front cover of the manual) shows the way of connecting in
mode one input – four outputs (Y IN/ABCD OUT).
Scheme No. 2 (on the inside back cover of the manual) shows the way of connecting in
mode four inputs – one output (ABCD IN/Y OUT).
The scheme on next page shows the use of two Line Midi Switchers for preamps
switching, especially those of them possessing the connection between signal ground
and grounding. In both of LMS-1 switchers should be set the same MIDI channel what
will assure synchronic switching.

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