Behringer T1953 - Manual (Page 20)

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TUBE ULTRAGAIN T1953
To eliminate this risk, the BEHRINGER TUBE ULTRAGAIN automatically disables the unbalanced jack in MIC
mode. Microphones can thus only be connected to the XLR connector.
Never switch on the +48 V supply when you use unbalanced microphones, as this could cause electrical
damage.
Some people hold that the sound of dynamic microphones is affected when the +48 V supply is on, or that
ribbon microphones cannot be operated from an input equipped with +48 V phantom power. None of these
statements is true. As a matter of fact, problems of this kind are caused by one of the following reasons:
1. When the output transformer of the microphone suffers from a short circuit or leakage current at any point,
disturbing noise, clicks or hum can occur. In this case, you should have the microphone repaired.
2. When you connect a microphone while the +48 V supply is switched on, it cannot be guaranteed that both
signal leads of the XLR connectors establish the electrical contact precisely at the same point of time.
Therefore, detrimental current could flow because the connection is temporarily unbalanced. We recommend
that you switch off the +48 V supply before you attempt to connect a microphone.
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Please make sure that you are using an appropriate microphone before you switch on the
+48 V supply. Read the operating instructions accompanying the microphone. Some condenser
mics might need another type of power supply, older dynamic microphones could be
damaged by the +48 V voltage, and unbalanced microphones should never be operated in
combination with a +48 V power supply.
5. INSTALLATION
5.1 Rack mounting
The BEHRINGER TUBE ULTRAGAIN fits into two standard 19" rack units of space (3 1/2" / 89.5 mm). Please
allow at least an additional 4" / 10 cm depth for the connectors on the back panel. Be sure that there is enough
air space around the unit for cooling and please do not place the TUBE ULTRAGAIN on high temperature
devices such as power amplifiers etc. to avoid overheating.
5.2 Mains connection
The mains connection of the TUBE ULTRAGAIN is made by using a mains cable and a standard IEC
receptacle. It meets all of the international safety certification requirements.
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Please make sure that all units have a proper ground connection. For your own safety, it is
advisable not to remove the ground connection within the units or at the supply, or fail to
make this connection at all.
Before you switch on the unit, check that it is configured to match your AC mains voltage requirements. If it
does not comply, then it is necessary to switch the operating voltage to the correct supply requirements
BEFORE turning on the unit, otherwise the unit could be severely damaged. You will find this combined fuse
holder/voltage selector at the back, adjacent to the IEC receptacle. IMPORTANT: This does not apply for
general export models which are built for one operating voltage only.
The AC voltage selection is defined by the position of the fuse holder. If you intend to change the operating
voltage, remove the fuse holder and twist it by 180 degrees before you reinsert it. Matching the two markers
monitors the selected voltage.
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If the unit is switched to another operating voltage, the fuse rating must be changed. See the
technical specifications in the appendix.
A safety fuse protects the unit from serious defects. If the fuse blows, this is a warning sign and always
indicates that the circuit is overloaded. The fault must always be repaired before the fuse is replaced. If the
safety fuse is faulty and needs replacing after the unit is repaired, please make sure that you replace it only
with the identical type and rating. NEVER use fuses of different ratings or cover faulty fuses with aluminium foil.
This can cause fire and electric shocks and will endanger your life and the lives of others.
5. INSTALLATION