Creek Audio - OBH-8 MKII - MM Phono Preamplifier
With modern amplifiers expected to cater for so many new source devices, the Phono capability, once very common, is one of those built-in features that has disappeared in recent times. The engineering team at Creek Audio has always loved the benefits of vinyl records and continues to work on technical and sonic improvements to its range of Phono amp options, be it the stand-alone OBH or plug-in Sequel types. Tasked with designing a replacement for the original OBH-8 MM Phono Pre-amp, the team came up with some valuable improvements and additional features. For the mk2 version a new type of low profile metal case has been developed to reduce the cost, without reducing quality.
The OBH-8mk2 has a completely new circuit design, utilising an integrated circuit MM stage. The signal required by most modern amplifiers is described as ‘LINE’ level which ranges from 200 mV and 500 milli-Volts sensitivity, with a flat frequency response. Unless your amplifier has a specific ‘Phono’ or Disc input, the level will be too low to play vinyl and the frequency response will be wrong. Hence the need for a Phono pre-amp.
The OBH-8mk2 is small device designed to boost the signal level by 40dB (x100) and change the frequency response to provide the most accurate reproduction of the recording.
The OBH-8mk2 is now produced in a smaller metal case to complement the Creek Evolution full sized range.
To enhance the performance, the power supply is split into a negative and positive voltage by a custom Creek discrete circuit. Two capacitance multipliers further filter the power supply, before they power the pre-amp circuitry, to reduce any unwanted ripple to virtually nothing. To reduce distortion Creek has also fitted constant current sources to the output of the gain stage, pushing it into Class A. This combined with a low output impedance make it suitable for driving long cables with ease.
The OBH-Uni is a multi-region, 24V, 0.5A power supply adaptor. Creek originally developed this power adaptor to simplify the requirements for selling OBH products in all countries. However, extensive listening tests and comparisons proved that this high efficiency regulated power adaptor can also extract the best performance from Creek’s OBH-15mk2 and OBH-8mk2 Phono Pre-amps, which have high-gain and are therefore more demanding of power supply purity. It is over-rated and can provide 4 times more power than is required to power a Phono pre-amp.
Strict international regulations make it unacceptable to use conventional linear power adapters because, if they are left permanently switched-on, their standby power will exceed the 0.1W limit. The latest OBH-Uni draws less than 0.1W when idle, or plugged-in but not used. It is also silent in operation, from zero to maximum current consumption.
- THD+NOISE AT 2VRMS OUTPUT - (40dB gain) @ 1kHz to 10kHz = <0.003%
- CHANNEL SEPARATION - >70dB
- FREQUENCY RESPONSE - 10Hz – 100kHz (+/-0.5dB)
- SNR - >76dB
- OVERLOAD MARGIN - >-21dB
- OUTPUT LEVEL - 6.1V RMS Maximum
- OUTPUT IMPEDANCE - <100 ohms="" li="">
- GAIN - 40dB fixed
- MATCHING - Resistance = 47k Ohms. Capacitance = 220pF
- SIZE - 100x48x80mm WxHxD
- WEIGHT - 0.4 kgs inc OBH-Uni power adapter
- POWER CONSUMPTION - 3 Watts
- MAINS VOLTAGES - 100V to 250V AC 50/60Hz
- MAINS CONNECTION - A clip-on plug is supplied for UK, North America and Europe
- FINISH COLOURS - Black Only