[Amps] soft start on filament

[Φραγκιαδάκης Παναγιώτης]

THANK YOU ALL FOR THE PERLAY

ok that explains why my 2x 4 400 in my linear reduse ther power bery fast 
well can i use a resistor in series to the filament or the time is still fast ?
and why the use 2 types of filament heat up the original 1 minute ?
and the fast heat up 
imean what is the need of fast vwarmup 
a frend of mine told me that becouse of war times for portable trancivers they need an instand warmup in order not use a lot of batery power and for instand transmiting ie grc9 output 2e22 tube 
is this true?
regards panos SV4JYI