I am in the process of converting an SII to 45's and have some questions. But first, thanks to everyone here for the invaluable information to help me get started.

Ok, here's my situation. I'm trying to fine tune the filament resistor values, I have the DCF supply installed, and I have standard 45 tubes. Base on data in this thread, I started with a pair of 0.25 ohm resistors, then took measurements: DCF supply voltage = 3.4Vdc, voltage across each 0.25 ohm resistor = 0.375V, voltage across filament = 2.66V, current through filament = 1.5A. This data was recorded after voltages stabilized.

So the filament current is at spec, but the voltage is 6.4% too high. To reduce the filament voltage, I can play around with increasing the resistor values, but if I did that, the current would go down (right?). So is there an achievable solution where the current is 1.5A and the filament voltage is 2.5V? Is hitting one target more important than the other? Any suggestions on what resistor value(s) to try next based on this data point?

Just to see if the filament is "behaving", I gave it 2.5Vdc with a power supply and it consumed 1.5A, so it seems ok.