Nobels A/B-MASTER User manual

Thank you for purchasing the NOBELS A/B-MASTER!
The A/B-MASTER is a high-quality universal A/B switchbox for music applications. It allows the
user to select between two different signal paths.
It is possible to switch two input signals alternately to one output. This is convenient when
playing two different guitars alternately over the same amplifier, for example.
Another application is the selection between two different outputs from one input. This could
be used to play one instrument alternately over two different amplifiers, for example.
The switching action is controlled from remote via a conventional foot switch. It is also possible
to control the A/B-MASTER from an external MIDI switcher, such as the NOBELS MS-4.
The A/B-MASTER is equipped with our new innovative T.S.S. (True Switching System), which
transfers the input signal(s) to the output(s) absolutely unadulterated without any loss in clarity
or punch. This system employs the highest grade audio relays, otherwise found in Hi-End
studio equipment.
As another unique feature the A/B-MASTER provides separate switches to connect or break
the individual ground connections of all in- and outputs. This is an important help in tackling
the most common hum problems, that can occur when several different pieces of equiment
are connected.
Power switch: In the leftmost position
the device is switched off.
The center position ("on") selects
the A/B-MASTER´s normal operating
mode. This enables the user to select
between the two different signal paths
"A" and "B" via a remote switch.
The rightmost position selects the units
"test" mode, which allows for a function
check without an external switch con-
nected.
"A" indicator: Lights when the "X" jack
is internally switched to jack "A".
"B" indicator: Lights when the "X" jack
is internally switched to jack "B".
Ground / auto mute switches: The left
three miniature switches cause the
signal grounds of the corresponding
in-/outputs to be disconnected in the
"lift" position (please refer to instruc-
tions for use).
The rightmost mini ature switch
causes the unused in-/output to be
shorted to ground automatically. This
eliminates noise problems that can
be generated by "open" amplifier
inputs.
DC in jack: The connection for a regu-
lated DC power adaptor to supply a
proper operating voltage to the A/B-
MASTER. Please refer to the technical
data section for details.
DC out jack: Further devices(e.g. effect
pedals) can be connected here for
feeding them off the A/B-MASTER´s
power supply.
This requires the external power
adaptor to match all necessary
specifications and to be able to supply
an adequate current.
Regarding polarity, plug size etc.
NOBELS follows the standard of the
world´s most popular effects lines so
there should be no problems to be
expected in most cases.
"A" jack: Serves as input A when using
two inputs and as output A when using
two outputs.
"B" jack: Serves as input B when using
two inputs and as output B when using
two outputs.
"X" jack: Serves as the output when
using two inputs or as the input when
using two outputs.
All signal connections are made using
regular instrument cables with mono
jack connectors.
Remote jack: The switching function
can be activated remotely by connec-
ting a regular foot switch (latched type)
here.
The A/B-MASTER may as well be ope-
rated from a MIDI switcher, such as the
NOBELS MS-4.
Hint: If a momentary foot switch is connected
instead of the latched type, the A/B-
MASTER will switch from "A" to "B" as
long as the switch is pressed and
return to "A" automatically as soon as
the switch is released.
When the switch is moved to the "test"
position the PRE-MASTER switches
from "A" to "B" automatically.
This function is only available when no
external switch is connected to the
"remote" jack.
Power indicator: The LED lights when
a proper operating voltage is supplied
and shows that the A/B-MASTER is
switched on.
A/B-MAS TE R S 1 - 0 4 052 7EN

Specifications subject to change without prior notice.
© Nobels Electronics, Barnerstr. 42, 22765 Hamburg, Germany, www.nobels.com
Owners manual
Instructions for use:
When using two input signals jacks "A" and "B" serve as inputs whereas jack "X" serves as the
output:
When going for two output signals jacks "A" and "B" serve as outputs whereas jack "X" serves
as the input:
Whenever signal connections are made between different devices with separate safety grounds
there is a chance of hum problems introduced by so called earth loops.
For this reason the A/B-MASTER provides a simple but effective option to break these
troublesome loops. To achieve this the user must simply set the "ground" switch of the input
or output in question to its upper "lift" position. Sometimes this might be necessary on several
in-/outputs.
The Interlock System:
Housings of the MASTER SERIES and COMPACT SERIES are mechanically 100% compatible.
Up to four units can easily be interlocked and mounted to a 19" standard tray using one rack
space:
Technical data:
Operating voltage : 9 ~ 12 V DC / 150 mA (regulated)
Current drain : 15 mA max.
Dimensions (mm) : 104 x 69 x 43
Signal-
source
Amp 1
Amp 2
AB
MASTER
A
B
X
Amp
AB
MASTER
Signal-
source
1
Signal-
source
2
A
B
X
ENGLISH
A/B-MAS TE R S 2 - 0 4 052 7EN
A/B-MASTER