Oracle Audio Technologies
PH200 Mk III phono preamplifier
4
Gain and Impedance settings
Moving Magnet:
The gain setting rocker switch # 3 is set at “ON” to set the gain at 42dB for both for both
Right and Left channels. The impedance setting toggle switch # 6 is set at 47k Ohms for
both Right and Left channels. All other switches must be set in the “OFF” position.
Capacitive option:
For fine tuning the capacitive charges it is possible to add a capacitor in addition to the
existing 150pf capacitor already in the circuit. When # 6 is in “ON” position the value of
the additional capacitor will be added to the 150pf. So if you add 150pf at C7 for the Left
channel and C12 for the Right channel the net result will be 300pf capacitance.
Important note:
The 2 middle holes of each of the black headers are not connected.
Only the holes at
both ends must be used ( see the 1.5k Ohms resistor in the picture ).
Moving coil:
The 4 position gain setting rocker switch # 1 is set at “ON” to set the gain at 62dB or switch
# 2 is set at “ON” to set the gain at 52dB for both the Right and Left channels. For low
output
MC
between 0,35 mV to 0.5 mV we suggest using #4 position for a 73dB gain. For
MC
with an output between 0,5mv to 1,5 mV we suggest to use the 62dB gain at #1. For
MC
with an output between 1,5mv to 3,0 mV we suggest to use the 52dB gain at #2
position
.
Important note 1 :
Note only one of the rocker switches should be at the ON position at the time. You can
experiment between different gain settings to get a better feel of the comfortable gain
range for the phono cartridge you are using.
Important note 2 :
The PH 200 Mk III phono amplifier is not designed to operate with phono cartridges under
0,35mV. For
MC
’s with output higher than 3.0mV use the 41.5dB gain of position
R7
.
