Sennheiser AC 2 User manual

Active Transmitter Combiner 4:1
AC 2
Instructions for use
11

12
Brief description
With the AC 2 4-to-1 active transmitter combiner, the signals
of up to four SR300IEMG2 transmitters can be combined
onto a single antenna. The AC 2 also incorporates DC distribu-
tion for powering the transmitters.
By using the GA 2 rack adapter, two AC 2 combiners or one
AC 2 combiner and one SR 300 IEM G2 stereo transmitter can
be mounted into a 19" rack.
Areas of application:
!Multi-channel in-ear monitoring systems for broadcast or
stage use
!Multi-channel systems suitable for any application where
talk-back signals are to be transmitted (e.g. studio)
Delivery includes
!1 AC 2 4-to-1 active transmitter combiner
!1 set of plastic feet
!Instructions for use
Note:
The NT 3 mains unit must be ordered separately.

13
Safety instructions
Caution!
Never open the unit! If units are opened by you in breach of
this instruction, the warranty becomes null and void.
Attention!
Make sure that the air vents of the unit are not covered or blo-
cked! Keep the unit away from central heating radiators and
electric heaters!
Caution!
Set up the unit on an even surface or mount it into a rack! Lay
the cables in such a way that no-one can stumble over them!
Danger!
Keep liquids and small parts which conduct electricity away
from the unit! Use a slightly damp cloth for cleaning the unit.
Do not use any solvents or cleansing agents!

14
Operating controls
Red LED for operation indication
On/off switch (POWER)
DC input (DC IN) for mains unit
Cable grip for power supply DC cable
Four DC outputs (DC OUT) for powering up to
four transmitters
Four BNC cables (RF INPUTS)
BNC socket (RF OUTPUT)
 






15
Putting the unit into operation
The below connection diagram shows the connections for a
4-channel system.
Setting up the unit
The unit is suitable for use as table top or can be mounted into
a rack.
왘For mounting the unit into a 19" rack, use the GA 2 rack
adapter (optional accessory).
왘For table top use, fix the plastic feet to the base of the unit.
Note:
Some furniture surfaces have been treated with varnish,
polish or synthetics which might cause stains when they
come into contact with other synthetics. Despite a tho-
rough testing of the synthetics used by us, we cannot rule
out the possibility of staining.

16
Connecting the transmitters
You can connect up to four SR 300 IEM G2 transmitters to the
combiner. The combiner incorporates DC distribution for
powering the transmitters.
왘Pass the cables coming from the combiner’s DC outputs
through the cable grips  at the rear of the transmitters.
왘Insert the hollow jack plugs into the sockets of the
transmitters.
Connecting the antenna
The combiner combines the transmission signals of up to four
transmitters onto a single antenna.
왘Connect the BNC cables of the combiner to the BNC
sockets of the transmitters.
왘Connect the telescopic antenna of one of the transmitters
to the BNC socket  of the combiner.
왘Pull the end cap to extend the telescopic antenna and align
it upwards.
왘When rack-mounting the combiner, the telescopic antenna
can be connected to the front of the GA 2 rack adapter by
using the AM 2 antenna mount (optional accessory).
Use a remote antenna (optional accessory) when the combi-
ner position is not the best antenna position for optimum
transmission.
 



17
Connecting the mains unit
The combiner is powered via the NT 3 mains unit. To switch the
combiner on, press the on/off switch (POWER). The red LED
lights up, indicating the the unit is ready for operation.
왘Pass the cable through the cable grip .
왘Insert the DC connector on the power supply cable into the
DC input .
Note:
As soon as the combiner is switched on, the built-in fan
starts producing a clearly audible operating sound and
ensures proper cooling of the unit.
Make sure that the air vents of the unit are not covered or
blocked.
If problems occur ...
The combiner does not transmit a signal
왘Check the connections of the NT 3 mains unit.
Disturbed RF transmission
왘Make sure that the antenna is connected correctly. Use
low-loss RF cables which are as short as possible.
If problems occur that are not listed above or if the problems
cannot be solved with the proposed solutions, please contact
your local Sennheiser agent for assistance.
 

18
Specifications
Active transmitter combiner 4:1
Frequency range 500 to 870 MHz
Distribution attenuation 0 dB (±1 dB)
RF input power max. 100 mW per input
Impedance 50 Ω
Power supply 12 V DC ±5 %
Current consumption max. 1.5 A +1 A for powering
the transmitters
Accessories
NT 3 Mains unit for AC 2 and four transmitters (e.g. SR 300 IEM G2),
output voltage: 12 V DC, output current: 2.5 A,
European version
NT 3-120 Mains unit for AC 2 and four transmitters (e.g. SR 300 IEM G2),
120 V version
NT 3-UK Mains unit for AC 2 and four transmitters (e.g. SR 300 IEM G2),
UK version
GZL 1019-A1 BNC-BNC coaxial cable, length 1 m
GZL 1019-A5 BNC-BNC coaxial cable, length 5 m
A 1031-U Passive UHF antenna
GA 2 19” rack adapter
AM 2 Antenna mount for mounting antennas to the front of
the GA 2
A 2003-UHF UHF directional antenna

19
ENGLISH
The guarantee period for this Sennheiser product is 24 months from the date of purchase.
Excluded are accessory items, rechargeable or disposable batteries that are delivered with the
product; due to their characteristics these products have a shorter service life that is principally
dependent on the individual frequency of use.
The guarantee period starts from the date of original purchase. For this reason, we recommend
that the sales receipt be retained as proof of purchase. Without this proof (which is checked by
the responsible Sennheiser service partner) you will not be reimbursed for any repairs that are
carried out.
Depending on our choice, guarantee service comprises, free of charge, the removal of material
and manufacturing defects through repair or replacement of either individual parts or the entire
device. Inappropriate usage (e.g. operating faults, mechanical damages, incorrect operating
voltage), wear and tear, force majeure and defects which were known at the time of purchase
are excluded from guarantee claims. The guarantee is void if the product is manipulated by non-
authorised persons or repair stations.
In the case of a claim under the terms of this guarantee, send the device, including acces-sories
and sales receipt, to the responsible service partner. To minimise the risk of trans-port damage,
we recommend that the original packaging is used. Your legal rights against the seller, resulting
from the contract of sale, are not affected by this guarantee.
The guarantee can be claimed in all countries outside the U.S. provided that no national law
limits our terms of guarantee.

53
EG-Konformitäts-Erklärung
EC Certificate of Conformity / Déclaration de conformité pour la CEE
Certificato di conformitá comunitario
Declaración de Conformidad / EG-Conformiteitsverklaring
SENNHEISER electronic GmbH & Co. KG
Am Labor 1, D-30900 Wedemark
erklären, dass das Produkt / declare that this device / déclarons que ce appareil /
declaramos que este aparato / dichiaria che questo appareccho / verklaren, dat det toestel
AC 2 Active Antenna Combiner 4:1
den einschlägigen Anforderungen der EG-Richtlinie 89/336/EEC bzw. der R&TTE-
Direktive 1999/5/EC entsprechen.
Zur sachgemäßen Umsetzung der in den EG-Richtli-
nien genannten Anforderungen
wurden folgende Normen herangezogen:
conform to the basic requirements of EEC Directive 89/336/EEC resp. R&TTE Directive
1999/5/EC. To effect correct application of the requirements stated in the EEC Directi-
ves, the following standards were consulted:
sont conformes aux prescriptions fondamentales dans la Directive de la CEE 89/336/
EEC or la Directive R&TTE 1999/5/EC. Pour mettre en pratique dans la règle de l’art les
prescriptions des Directives de la CEE, il a été tenu compte des normes suivantes:
complen los requimientos básicos de la normativa de la CEE 89/336/EEC resp. de la
normativa R&TTE 1999/5/EC. Con il fin de realizar de forma adecuada los requirimien-
tos referidos en las normativas de la CEE fueron consaltadas las siguientes normativas:
sono conformi alla normativa 89/336/EEC resp. alla normativa R&TTE 1999/5/EC. Per
un’appropriato risconto nell’ambito della normativa CEE sono state consultate le segu-
enti normative:
evereenkomt met de basiseisen van de EG-Richtlijn 89/336/EEC resp. de EG-Richtlijn
1999/5/EC. Om de eisen, die in de EG-Richtlijnen vermeld zijn, in juiste vorm om te zet-
ten, zijn van volgende normen gebruik gemaakt:
ETS 300 445 ETS 300 422
Klaus Willemsen,
Key Projects, Product Marketing
Wedemark, Oct, 2003