Filaments works from 3 to 6 volts and 1 to 3 amps.

Many radios run ac through the filaments. (no diodes, no cap)
What filament? Those numbers seem odd to me.
3V at 1A = 3 ohms. Many old radios use power resistors to limit the power in a filament. You could add a 3.0 power resistor in series with the filament and drive them directly from the 6.3V transformer.

 

Thank you for all your help.

My triodes are made by me, so I´m experimenting with different filaments configurations

Comercial tubes works with 6,3VAC, but it is easir to change the voltahe when is DC, so I use DC current for the filament

 

hi Rufius,
This circuit simulation uses a 500k potentiometer to set the +B voltage.
Add the R8, 27k and change R7 to a 5k6.

As you can see the plot shows a voltage +B range of ~30v through to ~ 300v.

Increase the wattage of R1 to 3Watt,

Do you follow OK.???
E

Ooook, now everything works nice. Thank you a lot

Also Thank you for the PDF about heatsinks. Now, I know how to calculate it