Safety; Design Features; Connection; Operation - Beyerdynamic DT 250 Notice D'utilisation

OPERATING INSTRUCTIONS
DT 250 / DT 252 / DT 280 / DT 290 / DT 291 /DT 287 / DT 297
Thank you for selecting one of the DT 200 series professional studio head-
phones or headsets. They have been made in Germany from high-grade
materials and assembled under stringent quality and performance tests to
provide you with a professional communications tool. Please take some time to
read through this instruction booklet to give you an idea of the design
criterion and some information on connection, use and maintenance.

1. Safety

When plugging in any of the DT 200 - series headsets to the drive amplifier, we
recommend that this is done before it is fitted over the ears for use. This will
give the technician the chance to check that the volume levels are not too high.
Please remember that the user could well be a highly-paid presenter and the
consequences of damaging his / her ears may well prove to be music to the ears
of the lawyer! The very low levels of distortion can make listening levels higher
than is perceived and we have to warn you that listening to programme or talk-
back at high levels for long periods can permanently damage your hearing.

2. Design Features

DT 250 / DT 252
The DT 250 / DT 252 is a closed dynamic headphone offering excellent
ambient noise isolation making it suitable for all kinds of applica tions in broad-
casting and recording studios. The headband and earphone cushioning systems
have been carefully designed for maximum comfort and unobtrusive style. The
powerful neodymium magnet system provides high-fidelity reproduction and a
balanced sound. The standard impedance is 80 Ω. Furthermore, versions with
250 Ω systems are available. The connecting cables to the ear monitors run
safely in the headband and the main connecting cable is terminated on one
side with a multi-pin connector.
DT 280 / DT 290
Same as DT 250, but featuring the dynamic hypercardioid DM 290 microphone.
The DT 280 / DT 290 headset is used in intercom and talkback systems as well as
other applications where a dynamic microphone is required. The DT 280 /
DT 290 V.11 has an integrated microphone preamp for AB-powering.
DT 291 / DT 297
Same as DT 250, but featuring an omnidirectional electret condenser micro-
phone (DT 291) or a cardioid condenser microphone (DT 297). The DT 291 PV /
DT 297 PV is equipped with an integrated preamp for phantom powering.
The DT 297 V.11 has an integrated microphone preamp for AB-powering.

3. Connection

The DT 250 / DT 252 headphones are supplied with an appropriate connecting
cable. The the DT 280 / DT 290 / DT 291 / DT 287 / DT 297 headsets are supplied
without connecting cable. For appropriate connecting cables, please refer to
"Optional Accessories". Direct solder connections can be made to all cables with
free ends (for cable connection refer to "Block Diagram"). Upon request the
required plugs can be connected at the factory.
It is important that the external equipment the studio headphones or the head-
sets will be connected to are of good quality and of the correct impedance and
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power ratings to get the best performance from them. Please refer to the
"Technical Specifications" for detailed information.
The microphone of the DT 280 / DT 290 headset is designed for balanced
connection. But it can be also connected to unbalanced microphone inputs.
The DT 291 PV or DT 297 PV headsets are suitable for the connection to
balanced microphone inputs with phantom power. At a distance of 5 cm the
microphone level is 13 mV or 250 mV.
Use the DT 280 / DT 290 V.11 or DT 287 / DT 297 V.11 headset with integrated
preamp for connecting to TV cameras with a microphone input for AB-
powering. At a distance of 5 cm the microphone level can be adjusted between
52 mV and 1.3 V at normal speech volumes. The supply voltage for the
pre-amplifier can vary between 6 - 27 V. The power consumption is at:
R vor 330 Ω
6 V
R vor 330 Ω
12 V
R vor 330 Ω
20 V
R vor 330 Ω
27 V

4. Operation

The head phones are fully adjustable and should be positioned for the best fit
over the ears. This will give maximum long-term comfort and will minimise
sound leakage or spill.
The microphone should be positioned to the side of the mouth, about
20 - 30 mm forward. This will keep it within the direct sound path but out of
breath stream, therefore minimising any 'pop' sounds.
All versions:
The microphone boom is rotatable so that the
microphone can be placed over the left or right
ear.
DT 290 V.11 DT 297 V.11
8 mA 6 mA
23 mA 20 mA
43 mA 40 mA
61 mA 57 mA
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