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 pre-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 Phono Pre-amp will work very well in the following system. Please note the speakers quoted may need to be different depending on the size of the room your system is to be used in.
The OBH-8mk2 Phono Pre-amp 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 a very impressive sounding phono stage”
ES – Hi-Fi Choice
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 makes 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 2V RMS output <0.003 – 20Hz to 20 kHz
Channel Separation at 1kHz >70dB
Frequency Response ref RIAA +/-1dB – 20Hz to 20kHz
Signal to Noise ratio at 2V output >74dB
Overload Margin 21.7dB
Maximum Output level 6V
Output Impedance 100 Ohms
Gain 40dB (x100)
Matching capacitance and resistance 100pF, 47k Ohms
Size: (Width x Height x Depth) 100mm x 37mm x 90mm
Power consumption (Total) <3W
OBH-UNI power adapter power consumption 100mW (idle)
OBH-UNI power adapter voltage input range 90V to 250V