The 0A2 and the 0D3 are both 150v gas regulator tubes, 7-pin mini and octal respectively.
You must provide the tube with a minimum 5mA more than the preamp circuit consumes (maximum 30mA or 40mA depending on the tube). I'm sorry I don't have the Anticipation manual at hand, but IIRC the preamp needs less than 10mA. You can do this with a high voltage supply and a dropping resistor, or with a current source. The original power transformer can't supply enough current, which is why this mod never appeared.
Since you have a 140v transformer, a fullwave bridge might give you 175v after the filter section. That leaves 25 volts to drop, but if the power line voltage changes 10% you'll have only 7.5v, or 42.5v. That's too much variation to get by with a simple resistor. So there are two practical answers:
1) Use a voltage doubler to get around 350v. Then drop 200v in a resistor - let's say 10K ohms which will give 20mA, half to the regulator tube and half to the preamp circuit. This is the circuit used in Foreplay III. The resistor will need to be rated at least 10 watts and will get hot!
2) Use a fullwave bridge to get 175v, and use a current source to supply 20mA to the regulator and preamp. This is how we do it in the Extended upgrade, except it's a hybrid shunt regulator instead of a gas reg tube (and it's dual mono).
Hope that helps. :^)
