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.
