Creek Audio OBH-11 User manual

Thank you for purchasing the OBH-11 Headphone Amplifier. You are now in
possession of a State of the Art product. The functions and operation of the OBH-11
are extremely simple. However, the following notes are provided to explain all
aspects of its design and use.
OVERVIEW
The OBH-11 is a miniature audio amplifier, designed
specifically to drive a single pair of low to medium
impedance (30
Ω -300 Ω ) headphones from a line level
source. It is more efficient to have a small amp to do
this rather than waste the power of a full size one when
only driving headphones.
The OBH-11 is compatible with any source at line level.
For example: an average output level CD player can be
connected directly to the input of the OBH-11, just as it
could also be used in conjunction with a stand-alone
pre-amplifier or integrated amplifier which doesn't have
a headphone output.
The OBH-11 is not designed to be connected to the
speaker output of an integrated or power amplifier.
Output level can be controlled by the high quality
volume control on the front panel.
Creek OBH -11
Designed in the UK .
CREEK OBH-11 SPECIFICATION
OUTPUT POWER > 10 mW into 30
ΩΩto 300 ΩΩloads
HEADPHONE IMPEDANCE 30
ΩΩto 300 ΩΩ
THD ≤≤0.05% at 1 kHz
SIGNAL TO NOISE RATIO >>7700dB
POWER CONSUMPTION < 4 VA
POWER SUPPLY 24V DC 150mA
SIZE 100mm x 130mm x 65mm
(4" x 5" x 2.5")
WEIGHT (NETT) 360 gms (12 ozs)
Creek Audio Ltd reserves the right to change or modify
the specification of its products without prior warning.
If within two years of purchase date your OBH 11 proves to be defective for any
reason other than accident, misuse, neglect, unauthorised modification, or fair wear
and tear, Creek Audio Ltd. will, at its discretion, replace the faulty parts without
charge for labour or return carriage within the U.K.
This warranty is valid only in the U.K. and given in addition to statutory rights.
Service enquiries outside the U.K. should be addressed first to the supplying dealer
and/or the Creek distributor/importer. Warranties granted in these countries are
entirely at the discretion of the distributor.
Creek Audio Limited
12 Avebury Court, Mark Road,
Hemel Hempstead HP2 7TA
England
Telephone: [phone] Fax: [phone]
Email: [email protected] Web: www.creekaudio.com
Operating
Instructions
WARRANTY

INPUT AND OUTPUT CONNECTIONS
The OBH-11 has two pairs of stereo phono sockets (RCA jacks) on the rear panel.
The first pair is the Input from any line level source, direct from the source or via the
tape output of an amplifier. The second pair of sockets, marked ‘Output’, are to chain
link the signal onto the next component in the system. Therefore, the OBH-11 can
be driven from the Tape Output of an amplifier and the second set of sockets can be
used to link the signal to the Tape recorder input. There is a 2.1mm DC power jack,
with centre positive pin, for connection to a custom Creek OBH type power supply
adaptor. On the front panel there is one 1/4" (6.3mm) stereo socket, for plugging in
the headphones.
INSTALLATION AND OPERATION
Connect the OBH power supply adaptor to the mains socket. Find a suitable place
for the OBH-11 and plug the DC power lead into the rear panel DC jack socket.
Connect a pair of high quality interconnect cables from the output of the source to
the input sockets on the rear of the OBH-11. Refer to the wiring diagrams showing
the different options for connecting the OBH-11 to your system.
Plug the headphones into the socket on the front panel. Push the On/Off button on
the rear to power-up the OBH-11. The small green LED on the front panel will light
when it is ready for use. The front panel volume control should be set to the desired
signal level.
POWER SUPPLY REQUIREMENTS
In common with all electrical appliances, the OBH-11 needs a power source. The
requirements for the OBH-11 is 24 Volts DC at 150 milli Amps current. A custom
power supply has been provided to run it, which must be connected to the unit via
the DC inlet (2.1mm positive centre pin power jack) on the rear panel. The power
supply adaptor should be plugged into the mains socket which should be matched
for the voltage of the country of use.
N.B. Due to the circuitry charging-up it is normal to hear a small thump through the
headphones during switch-on.
Note 1: The OBH should be placed away from transformer hum fields for
low noise operation.
Note 2: When new, it is necessary for the OBH to be ‘burned-in’ for at least
24 hours before its full sound quality potential can be realised.
Note 3: Listening to excessive sound pressure levels can seriously damage
your hearing. Be careful and enjoy the music.
WIRING DIAGRAMS
OBH
Power Supply
CD
Player
OBH -11
Option 1
Option 2
Option 3
OBH
Power Supply
CD
Player
OBH -11
Amplifier
Amplifier
Tape
Deck
OBH -11
CD
Player
OBH
Power Supply