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RE: RC

If there is anything wrong with doing it this way, anyone can jump in and let us know.

I had the impression that your B+ for the linestage is already regulated upstream. If so, you could tap voltage for the phono stage off the last node that feeds the linestage circuit, which should be at 400V, if memory serves. Then you need to have at least a ballpark idea of how much current is needed for the phono stage. Let's say it's 50mA, just for the sake of calculation. And let's say you want to drop the voltage to 250V. So, you need a resistor to go in series between the 400V node in the linestage PS to a node that feeds the phono stage. This resistor must drop 150V. Here is where Ohm's Law comes in handy. Voltage (V) = current (I, in Amperes) times resistance (R, in ohms). Rearranging the equation to solve for R, we have R = V/I or R = 150/.05 = 3000 ohms.

You also need to take into account the power, P (in Watts)= I*V = .05A*150V = 7.5W. Use at least a 10W resistor; I have used 12W Mills resistors in a similar situation. They get hot; don't worry.
Then you could place an additional filter cap in parallel with the resistor, on the phono stage side. This will afford some additional isolation of the phono stage PS from the linestage PS. 50uF or 100uF would be acceptable values, for example. More or less capacitance could also be used with various consequences.

A possible negative consequence of doing it this way is that you are now pulling that extra 50mA from the same source that you want to supply 400V to your linestage. This might drop the voltage for the linestage below 400V. What will happen depends upon the relative current demands of the two stages. But you probably could live with a slight drop in the linestage V.

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