The function of the Creek OBH-22 passive pre-amplifier is to provide input selection and volume adjustment to a Hi-Fi system either from a remote control handset or by controls on the front panel. A Passive Pre-amp is really a contradiction in terms, as a passive circuit cannot amplify anything. It has the simplest form of control that can be applied to an audio signal path. This has the effect of making it impossible to distort or otherwise colour the sound of a signal passing through it.
The OBH-22 consists of a high quality 27mm ALPS Blue Velvet motorised potentiometer and two relays gold contact which select the desired input, together with a muting relay that shorts the signals to ground when active but is not in the signal path for normal operation.
A built-in micro-controller decodes the infra-red signals transmitted by the handset and translates them into commands which power the motorised potentiometer 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 input sensitivity of the power amplifier that is being used is sufficient 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 input 1 is connected.
Power for the OBH-22 comes from the Universal Creek OBH-Uni power supply that can operate in any country and is supplied with a range of snap-on mains plug connection.
Technical Specifications
| Input Impedance |
< 20k Ohm |
| Output Impedance |
0 - 20k Ohm |
| Separation |
> 80 dB's @ 1kHz |
| Attenuation |
0 - 90 dB's |
| Inputs |
3 Stereo pairs, inc Tape |
| Outputs |
2 Stereo pairs, 1 fixed, 1 variable |
| Relay Muting Factor |
> 90dB's |
| Weight |
600g with OBH-Uni power supply
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| Size W/H/D |
150 x 100 x 66mm |
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