Creek Audio OBH18 Instruction

The function of the OBH-18 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 Creek OBH-18 phono pre-amplifier is designed to boost the signal and intro­duce an R.I.A.A. frequency response characteristic.

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.

Most moving magnet cartridges will be properly matched by
using the OBH-18. By plugging the signal leads from your
turntable into the OBH-18 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 OBH­18 ground terminal.

The output from the OBH-18 can be connected to most
integrated amplifier’s and pre-amplifier's line inputs via a
regular Phono to Phono (RCA to RCA) stereo interconnect
lead.

CREEK OBH-18 SPECIFICATION

GAIN 37 dB

FREQUENCY RESPONSE 20 Hz to 20 kHz ± 0.25 dB

SIGNAL TO NOISE RATIO - 86 dB

TOTAL HARMONIC DISTORTION < 0.03%

R1AA DEVIATION ± 0.1 dB

OUTPUT 250 mV

OUTPUT IMPEDANCE <100

W

INPUT SENSITIVITY / IMPEDANCE 3.5 mV/ 47 KW/ 220 pF

OVERLOAD MARGIN 25 dB

MATES WELL WITH CARTRIDGES WITH 2.5 mV - 5.5 mV output

DIMENSIONS 150 x 100 x 66 mm

POWER SUPPLY VOLTAGE 24V DC 30 mA

Supplied with an OBH-1 Standard Power Supply,

220-240V 50Hz or 110-120V 60Hz

Creek Audio Ltd reserves the right to change or modify the specification

of its products without prior warning.

Creek OBH-18

Designed and made in the UK.

Operating

Instructions

Creek Audio Ltd.

12 Avebury Court, Mark Road, Hemel Hempstead HP2 7TA, England
Telephone: [phone] Fax: [phone]
E-mail: [e-mail] Web: www.creekaudio.com

POWER SUPPLY REQUIREMENTS WIRING THE OBH-18

Note 1.

The OBH-18 should be placed away from power supply hum fields

for the lowest noise operation.

Note 2.

It is necessary for the OBH-18 to be 'burned-in' for at least 24 hours

before its full sound quality potential can be realised.

CONNECTIONS

With its enhanced drive capability coupled with lower output impedance, the
OBH-18 phono pre-amplifier can now drive longer cables than its predeces­sor, the OBH-8.

OUTPUT

The output impedance of the OBH-18 is < 750 Ω, and it can be used to drive
long interconnects, without loss, provided they are not high capacitance
types.

In common with all electrical appliances, the OBH-18 requires a power
source.

The requirement for the OBH-18 is for 24 Volts DC at 30 milli Amps current.
A Creek OBH-1 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 rear panel. It may be left switched on permanently
as it draws very little power.

N.B. Due to the inherent muting circuitry in the OBH-18 the signal will

take a few seconds to be heard after the power is switched on.

Keep the main amplifier’s volume control at minimum to avoid

hearing any unpleasant noises during the on/off phase.