Creek OBH-22 Brochure

SPECIFICATIONS

OBH-21 OBH-21SE

Output power > 10 mW into 30W to 300W loads As per OBH-21
Headphone Impedance 30W to 300W As per OBH-21
Total Harmonic Distortion < 0.01% at 1 kHz < 0.005% at 1 kHz
Signal to noise ratio > 70 dB > 70 dB
Power consumption < 4 VA < 6 VA
Power supply requirement 24V DC, 150mA, centre positive 24V DC, 150mA
Preferred Power supply OBH-1 (un-regulated) OBH-2 (regulated)
Size 180 x 100 x 66 mm As per OBH-21
Weight (Nett) 360 g As per OBH-21
Recommended Power Supply OBH -1 OBH-2

OBH-15 MM MC OBH-18

Gain 37 dB 56 dB 37 dB
Frequency Response 20 Hz to 20 kHz ± 0.25 dB As per MM As per OBH-15 MM
Signal to Noise Ratio - 83 dB - 75 dB -83 dB
Total Harmonic Distortion < 0.03% < 0.05% < 0.03%
R1AA deviation ± 0.5% ± 0.5% ± 0.5%
Output 250 mV 250 mV 250 mV
Output Impedance <100 Ω <100 Ω <100 Ω
Input sensitivity / impedance 3.5 mV/ 47 KΩ / 220 pF As per MM As per OBH-15 MM
Input sensitivity / impedance 0.5 mV/ 1000 W / 3300 pF As per mm
Overload margin 22 dB 20 dB 25 dB
Mates well with MM cartridges 2.5mV-5mV output 2.5mV-5.5mV output
Mates well with MC cartridges 0.5 mV - 1 mV output
Dimensions 180 x 100 x 66 mm As per MM As per OBH-15
Recommended Power Supply OBH-2 220-240V 50Hz or 110-120V 60Hz OBH-1

OBH-22

Input Impedance < 20 kW
Output Impedance 20 kW
Separation > 80 dB's @ 1kHz
Attenuation 0 - 90 dB's
Inputs 3 Stereo pairs, inc Tape
Ouputs 2 Stereo pairs, 1 fixed, 1 variable
Relay Muting Factor > 90dB's
Power Requirements 24v @ 60 mA
Power Consumption 2W max
DC Connector Type 2.1 mm female DC jack
Input & Mute indication 2 LED
Size 150 x 100 x 66 mm
Weight 610 g
Recommended Power Supply OBH-1 220-240V 50Hz or 110-120V 60Hz
Supplied with Creek ARC53 System Remote Handset

OBH SERIES

OBH SERIES

PR

PR

ODUCT

ODUCT

CCAATTAL

AL

OGUE

OGUE

Designed and manufactured in England

12 Avebury Court, Mark Road, Hemel Hempstead HP2 7TA England

Phone: [phone] Email: [e-mail] Web: www.creekaudio.com

HEADPHONE AMPLIFIERS

Creek headphone amplifiers eliminate the need to use a full size amplifier
for boosting the power when only headphones are used. An average output
level CD player or tuner can be connected directly to the input of the
headphone amplifier.

Creek’s OBH-21 & OBH-21SE incorporate advanced circuitry utilising
professional standard operational amplifiers. The discrete transistor
technology used in earlier model Creek headphone amplifiers has been
replaced by high-grade integrated circuits providing a capability to drive

different types and impedances of headphones without problem.

There are two 1/4" (6.3mm) stereo headphone jacks on the front panel of both models. The output level
is regulated by the volume control on the front panel. When using the OBH-21 one source can be
amplified as the headphone amplifier has only one stereo input. It has stereo phono sockets (RCA jacks)
on the rear panel for input from any line level source, together with a DC power jack. In common with
all electrical appliances, the OBH-21 requires a power source. A custom power supply is provided, 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 may vary depending on country of use.

The SE version features internally advanced circuitry to split the power supply from a single positive to
a split positive/negative supply, which allows circuits to be DC coupled and to eliminate capacitors.
Higher grade components are used in the SE version. It also features two pairs of stereo Phono sockets
(RCA jacks) on the rear panel for input from any line level source and chain linking to another product
in a tape loop circuit. The DC power jack for connection to a custom OBH high-grade power supply
adaptor is also located on the rear panel.

The OBH-21 can also be used in conjunction with other Creek OBH series products. It also functions
with a stand-alone pre-amplifier or integrated amplifier without headphone output, connected in the
tape loop.

PHONO PREAMPLIFIERS

With modern amplifiers expected to cater for so many new devices, the Phono capability has frequently
been one of the features to disappear. Creek Audio has always been aware of the benefits of vinyl - that
is why it continues to provide a number of Phono stage options.

The OBH-15 Phono pre-amp can drive long cables, due to its low output impedance. It has combined
the high quality discrete semiconductor circuitry of the earlier Creek OBH-8 and OBH-9 input and gain
stages, and added improved open loop gain by cascading them, prior to the selector switch and combined
passive RIAA circuit.

Separate Burr-Brown professional grade low-noise op-amps are used for each channel to buffer the
output signal and provide a very low impedance drive to any pre-amp or integrated amplifier. The OBH­15 can switch from moving magnet to moving coil cartridges, via a simple push button on the rear panel.

As the OBH-15 has two input circuits, optimised for each type of cartridge it allows for the connection of two
turntables. A high gain MC version, for low output MC cartridges, is available to order. The OBH-15 has a
built-in high performance power supply regulator circuit which makes it immune from power supply
fluctuations so, it can be used with the unregulated OBH-1 6 Watt power supply. It will sound better with the
regulated 12 Watt OBH-2, which is available as an option.

Internally, the OBH-15 has been built to the highest standards using a
glass-fibre double sided, plated through hole PCB and very high-grade
components. The OBH-15 looks the part too! Designed to complement the
Creek range of amplifiers, tuners and CD players, the OBH range features an
impressive 4mm thick solid aluminium front panel in a silver finish. The
remainder of the 150mm deep extruded aluminium case is painted black, so
the product all but disappears.

The function of the OBH-18 is to boost the level and correct the frequency
response of a low level signal coming from a moving magnet phono pick-up on a
conventional turntable. The signal required by most modern amplifiers is
described as being 'LINE' level, which is, in technical terms, between 200 and 500
milli-Volts with a flat frequency response. Unless your amplifier has a specific
'Phono' or Disc input, the level will be too low and the frequency response will
be wrong. The OBH-18 is designed to boost the signal and introduce an
R.I.A.A. frequency response characteristic.

PASSIVE PREAMPLIFIER

The function of the Creek OBH-22 passive pre-amplifier is to provide input
selection and volume adjustment to a Hi-Fi system from an armchair, via
infra-red remote control. The unit can also be controlled directly from the
front panel.

The OBH-22 consists of a high quality motorised volume potentiometer, and

two stereo relays which select the desired input plus tape output, together with
a muting relay that can short the signals to ground. A built-in micro-controller decodes the infra-red signals
transmitted by the handset and translates them into commands which activate the motorised potentiometer
and the muting and input selection relays. After each operation, the micro-controller turns itself off to avoid
any possibility of interfering with the main music signal. LED's are used to indicate the status and mode of
operation.

The OBH-22 is purely passive and does not introduce any gain or distortion into the signal path. It is
therefore suitable to be used as a control pre-amplifier, provided the sensitivity of the power amplifier that is
being used is high enough to be driven directly from the source. i.e. CD player or tuner etc.

The volume control can be operated manually at any time, whether the OBH-22 is powered or not, but
without power only Line 1 can be utilised.