G-Lab M4L User Manual

Instrukcja obsługi

User Manual

Bedienungsanleitung

Midi 4 x Loop

M4L

4

1

Version 1.0

Table of contents

Structure ___________________________________________________ 2
Scheme and signal path description ____________________________ 4
Manual loops switching_______________________________________ 4
MIDI channel setting _________________________________________ 4
Controlling via MIDI commands ________________________________ 4
DS1 micro switch ____________________________________________ 6
DS2 micro switch ____________________________________________ 6
Power supply _______________________________________________ 6
Parameters _________________________________________________ 7
Possible using of the M4L_____________________________________ 7
MIDI implementation chart ____________________________________ 9
EMC/EMI & Certificate of conformity ___________________________ 11

2

Dear Customer,
Congratulations for choosing our G LAB product!

MIDI 4 x LOOP (M4L) is a loops’ switcher controlled by MIDI interface
(by Program Change or Control Change commands) or manually, by using
the buttons. Using the MIDI commands it is also possible to mute the signal
(e.g. for silent tuning). M4L can be controlled by every MIDI controller and it
is particularly recommended as an extension of the G LAB guitar system
controllers GSC.

Basic characteristics:

- four bypassed (by electro mechanic relay) loops to connect the pedal
effects or serially connected sets of effects,

- muting circuit based on opto elements,

- MIDI THRU connector to connect other MIDI devices,

- power supply and active loop indicators,

- four buttons for loops’ manual on/off switching,

- power supply 9V DC (direct current).

Structure

1 - Signal output connector 13 - Signal input connector
2 - LOOP 4 signal input (RETURN) 14 - MIDI input
3 - Power supply connector 15 - MIDI copy (THRU)
4 - LOOP 4 signal output (SEND) 16 - Loop 4 status indicator
5 - LOOP 3 signal input (RETURN) 17 - Loop 4 on/off button
6 - MIDI channel settings switcher 18 - Loop 3 status indicator
7 - LOOP 3 signal output (SEND) 19 - Loop 3 on/off button
8 - LOOP 2 signal input (RETURN) 20 - Loop 2 on/off button

9 - LOOP 2 signal output (SEND) 21 - Loop 2 status indicator
10 - DS1 and DS2 micro switch 22 - Loop 1 on/off button
11 - LOOP 1 signal input (RETURN) 23 - Loop 1 status indicator
12 - LOOP 1 signal output (SEND) 24 - Power supply indicator

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4

Scheme and signal path description

M4L has true passive signal path (without signal boosting and buffering
elements). Due to this the M4L doesn’t influence the guitar tone (doesn’t
change the tone and doesn’t cut the signal). It is recommended to use the
M4L to “exclude” from the effects’ signal path the effects without true bypass
function. Controlling by MIDI provide galvanic separation from controlling
device. Every time after switching on the power supply four effect loops are
switched off and the signal path is “opened”.

Manual loops switching

For manual loops switching there are used four buttons signed LOOP1,
LOOP2, LOOP3 and LOOP4. To switch on/off the loop press corresponding
button.

MIDI channel setting

To set the MIDI channel use the rotatable knob signed as MIDI
CHANNEL. To switch the channel use the small screwdriver to turn smoothly
central part of the switcher to the right or to the left. The arrow-head indicates
set channel (letter A, B, C, D, E, F correspond successively with the channel
numbers 10, 11, 12, 13, 14, 15, and number 0 indicates channel 16).

Controlling via MIDI commands

M4L can by controlled by Program Change commands. The table below
shows the Program Change command functionality.

LOOP

PROG. CH.

12

MUTE

1X OFF OFF OFF
2X ON OFF OFF
3X OFF ON OFF
4X ON ON OFF

5

LOOP

PROG. CH.

34

MUTE

X1 OFF OFF OFF
X2 ON OFF OFF
X3 OFF ON OFF
X4 ON ON OFF

LOOP

PROG. CH.

1234

MUTE

100 ON ON ON ON ON
101 RESTORE OFF

X – every value from 0 to 9 range

The units’ digit of program number defines the state of LOOP3 and LOOP4,
the decimal digit of program number defines the state of LOOP1 and LOOP2.
Receiving of the command which units’ digit or decimal digit has out of range
value causes ignoring that digit(s) an d considering th e digit with correc t value.

M4L can be controlled by individual Control Change type command or
individual controllers of particular functions. The table below shows the
Control Change commands functionality.

CONTROL CHANG E

NUMBER VALUE

0 - 63 LOOP1 OFF

80

64 - 127 LOOP1 ON

0 - 63 LOOP2 OFF

81

64 - 127 LOOP2 ON

0 - 63 LOOP3 OFF

82

64 - 127 LOOP3 ON

0 - 63 LOOP4 OFF

83

64 - 127 LOOP4 ON

0MUTE ON

7

1-127 MUTE OFF

CONTROL CHANG E

LOOP

NUMBER VALUE

12

MUTE

1X OFF OFF OFF
2X ON OFF OFF
3X OFF ON OFF

89

4X ON ON OFF

6

CONTROL CHANG E

LOOP

NUMBER VALUE

34

MUTE

X1 OFF OFF OFF
X2 ON OFF OFF
X3 OFF ON OFF

89

X4 ON ON OFF

X – every value from 0 to 9 range

CONTROL CHANG E

LOOP

NUMBER VALUE

1234

MUTE

100 ON ON ON ON ON

89

101 RESTORE OFF

DS1 micro switch

DS1 micro switch connects controlling circuit ground to main signal

ground. If the M4L’s 9V power supply circuit is fully separated from ground
(isn’t connected with any ground) the DS1 switch should be switched to ON
position.

DS2 micro switch

DS2 micro switch enables/disables the silent switching function. In order

to activate the function that mutes the loops switching clicks the DS2 switch
should be switched to ON position. The DS2 switch should be switched to
OFF position when in the signal path after the M4L there is another device
muting the switching clicks.

Power supply

M4L should be supplied from 9V (DC) external adaptor (efficiency 100 mA
or more). Before plugging the power supply check the pin polarisation. M4L is
protected against opposite polarity (minus as center).
If this protection switches on it is needed to disconnect the power supply and
wait few minutes before reactivation of the device.

ATTANTION!: Damage of the M4L caused by improper power supply causes

the loss of the warranty.

7

Parameters

Dimensions (depth x width x height) 270 x 70 x 38 mm
Weight 620 g
Maximal input signal 30 dBu
Power supply 9V DC (8,7 to 9,4V)
Power consumption 0,1 A

Possible using of the M4L

Below are shown the possible schemes of M4L connection with the guitar

system.

Scheme of M4L connection to the amp’s effects loop

8

Scheme of adding four effects loops to the GSC controller

Scheme of the system with the M4L connected to the amp input and the GSC

in the effects loop

9

MIDI implementation chart

G LAB MIDI 4xLOOP M4L rev. 1.04 10.01.2009

Function Transmitted Recognised
Basic Channel

Default X 1
Changed X 1-16

Mode

Default
Messages X X
Altered

Note Number X X

True Voice X X

Velocity

Note ON X X
Note OFF X X

After Touch

Keys X X
Channels X X

Pitch Bend X X
Control Change X 7, 80-83,89
Prog Change X 1-4,10-14,20-24,30-34,40-44,100-101
System Excl. X X
System Common

Song Pos X X
Song Sel X X
Tune X X

System real time

Clock X X
Commands X X

Aux Messages

Local ON/OFF X X
All Notes OFF X X
Active Sense X X
Reset X X

X: NO

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11

EMC/EMI & Certificate of conformity

EMC/EMI
This device has been designed and manufactured to conform with directives

and standards in the field of safety operations and electromagnetic
interference.
This device uses and can radiate radio frequency energy and, if not installed
and used in accordance with the instructions, may cause harmful interference
to radio communications. However in spite of performing below standards
there is no guarantee that interference will not occur in a particular
installation. If this device does cause harmful interference to radio or tele­vision reception which can be determined by turning the device on and off,
the user is encouraged to try to correct the interference by one or more of the
following operations:

● Reorient or relocate the receiving antenna.

● Increase the separation between the device and receiver.

● Connect the device into an outlet on a circuit different from that to

which the receiver is connected.

● Contact with the manufacturer.

● Consult the dealer for help.

Certificate of Conformity

ELZAB SA, ul. Kruczkowskiego 39, 41-813 Zabrze, Poland,
hereby declares on own responsibility that the following product:

MIDI 4 x LOOP (G LAB M4L)

that is covered by this certificate and marked with CE 07 label conforms with
following standards:

PN-EN 60065:2004

Safety requirements for mains operated electronic and
related apparatus for household and similar general use

PN-EN 55103-1:1998

Product family standard for audio, video, audio-visual and
entertainment lighting control apparatus for professional
use. Part 1: Emission.

PN-EN 55103-2:1998

Product family standard for audio, video, audio-visual and
entertainment lighting control apparatus for professional

use. Part 2: Immunity.
with reference to regulations in following directives:
73/23/EEC, 2004/108/EEC

Issued in Zabrze, January 2009

Jerzy Biernat

President of the ELZAB SA Board of Directors

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DO NOT PLACE THIS PRODUCT INTO THE WASTE CONTAINER !

This device is marked with a cross-lined waste container symbol
according to 2002/96/EU Directive on Waste Electric and Elec­tronic Equipment.
Such marking informs that after usage equipment can not be

trashed together with other household waste.
An user obligation is to return wasted equipment to a party collecting wasted
electric and electronic equipment. Parties collecting such equ ipment organise a
system, including local collection points, shops and other units, allowing to
return such equipment. This Directive assures an user free of charge utilisation
of such delivered equipment.
This device is made of materials which can be recycled or utilised after
becoming out of use. Proper handling of wasted electric and electronic
equipment reduce demand for row materials and contri bute in avoiding harmful
consequences for environment and health of people caused by dangerous
components and not proper storing and utilising of such equipment.

Owner Manual, Drawing No. G47INA00

Nr rys. G03IN000

COMPANY ADDRESS

ELZAB SA

ul. Kruczkowskiego 39, 41-813 Zabrze, Poland
phone: [phone], fax: [phone]

Sales & Export Department ......................................

phone: [phone] ext. 34, 39, 64
[phone] ext. 308, 366, 468
e-mail: [e-mail]

Technical Support .....................................................

phone: [phone] ext. 64
[phone] ext. 308
e-mail: [e-mail]

www.glab.com.pl

G LAB is a brand of ELZAB SA