Creek Audio OBH-8 User manual

Operating
Instructions
The function of the OBH-8 and OBH-9 is to boost the level and correct the frequency
response of a low level signal coming from a 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-8 and OBH-9 are designed to
boost the signal and introduce an R.I.A.A. frequency response characteristic. The
OBH-8 Special Edition is an audiophile version of the OBH-8 and operates in every
respect like the OBH-8.
INPUT AND OUTPUT CONNECTION
The output from the turntable is normally terminated on
two ’Phono’ plugs or RCA jacks. The level is dependent
on the type of cartridge used, and in the case of Moving
Magnet will normally be around 2-5 milli Volts and for
Moving Coil - 200 - 500 micro Volts. Low output MC
cartridges will require the higher gain of the OBH-9.
Most MM or high output MC cartridges will be properly
matched by using the OBH-8 or OBH-8SE. By plugging
the signal leads from your turntable into the OBH-8 or 9
input, the signal will be boosted to ’LINE’ level at its
output. To prevent hum pick-up, it may be necessary to
join the turntable’s earth lead to the OBH-8/9 ground
terminal.

The output from the OBH-8/9 can be connected to most integrated and preamplifier’s line
inputs via a regular Phono to Phono (RCA to RCA) stereo interconnect lead.
POWER SUPPLY REQUIREMENTS
In common with all electrical appliances, the OBH-8/9 requires a power source. The
requirement for the OBH-8/9 is for 24 Volts DC at 30 mill! Amps current, or higher. An
OBH-1 standard power supply, or OBH-2 high grade power supply, dedicated for the local
voltage and plug type, has been provided. It has a thin cable exiting from it, with a 2.1mm
positive centre pin DC power jack fitted on the other end. It should be connected to the
Phono amp via the DC inlet on its rear panel.
To operate the phono amp it is necessary to switch-on the unit by pushing the power button
on the front panel.
N.B. Due to the inherent muting circuitry in the OBH-8 & 9 the signal will take a few
seconds to be heard after the power is switched on. Keep the main amp’s volume
control at minimum to avoid hearing any unpleasant noises during the on/off phase.
WIRING THE OBH-8 AND OBH-9
Rear of Amplifier
Note 1. The OBH should be placed away from transformer hum fields for the lowest
noise operation.
Note 2. It is also necessary for the OBH to be ’burned-in’ for at least 24 hours
before its full sound quality potential can be realised.

CREEK OBH-8 SPECIFICATION
GAIN 37 dB
FREQUENCY RESPONSE 20 Hz to 20 kHz ± 0.25 dB
SIGNAL TO NOISE RATIO -82dB
TOTAL HARMONIC DISTORTION < 0.05%
R1AA DEVIATION ± 0.25 dB
OUTPUT 250 mV
OUTPUT IMPEDANCE 750 Q
INPUT SENSITIVITY AND IMPEDANCE 3.5 mV/ 47 kQ / 220 pF
OVERLOAD MARGIN 22 dB
MATES WELL WITH CARTRIDGES WITH 1.5 mV to 5.0 mV output
DIMENSIONS 100 x 100x63 mm
POWER SUPPLY VOLTAGE 24V DC 30 mA
Supplied with an OBH-1 Standard Power Supply, 220-240V 50Hz or 110-120V 60Hz
CREEK OBH-8SE SPECIFICATION
GAIN 37 dB
FREQUENCY RESPONSE 20 Hz to 20 kHz ± 0.25 dB
SIGNAL TO NOISE RATIO -86dB
TOTAL HARMONIC DISTORTION < 0.03%
R1AA DEVIATION ± 0.1 dB
OUTPUT 250 mV
OUTPUT IMPEDANCE 7500
INPUT SENSITIVITY AND IMPEDANCE 3.5 mV/ 47 kQ / 220 pF
OVERLOAD MARGIN 25 dB
MATES WELL WITH CARTRIDGES WITH 1.5 mV to 5.0 mV output
DIMENSIONS 100 x 100 x 63 mm
POWER SUPPLY VOLTAGE 24V DC 30mA
Supplied with an OBH-2 High Grade Regulated Power Supply, 220-240V 50Hz or
110
-
120V
60Hz

CREEK OBH-9 & OBH-9SE SPECIFICATION
OBH-9 OBH-9SE
GAIN 56 dB 65 dB
FREQUENCY RESPONSE 20 Hz to 20 kHz ± 0.25 dB
SIGNAL TO NOISE RATIO -75dB - 70 dB
TOTAL HARMONIC DISTORTION < 0.05% < 0.05%
R1AA DEVIATION ± 0.5% ± 0.5%
OUTPUT 250 mV 250 mV
OUTPUT IMPEDANCE 750 D 750 Q
INPUT SENSITIVITY / IMPEDANCE 0.5 mW 1000 0 / 3300 pF
INPUT SENSITIVITY / IMPEDANCE - SE 0.15mV/1000Q/3300pF
OVERLOAD MARGIN 20 dB 25 dB
MATES WELL WITH MC CARTRIDGES 0.5 mV -1 mV output
SE MATES WELL WITH MC CARTRIDGES 0.15 mV -0.3 mV output
DIMENSIONS 100 x 100 x 63 mm
POWER SUPPLY VOLTAGE 24V DC 30mA
Designed and made in the UK.
Both supplied with an OBH-2 High Grade Regulated Power Supply, 220-240V 50Hz or
110-120V’60Hz
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2 Bellevue Road, Friern Barnet, London N113ER, England
Tel: + 44 (0)20 - 8361 4133 Fax: + 44 (0)20 - 8361 4136
E-mail: [e-mail] Internet: wv7w.creekaudio.co.uk