[Amps] Switching Supplies for High Current Filaments

[Patrick Barthelow]

Are there any sensibly priced switching supplies (even surplus)  that are small and light, that could power some of the QRO tubes
with high current filaments?   Would, say, a  5v, 30A switcher which could power a pair of 3-500Zs, be economically 
competitive with a 5V 30A transformer, and even if it is not directly, it might still be worthy of consideration 
if it was small enough, and light enough to significantly lower size and weight in an RF deck? 
Would cold start surge current be a problem for switcher implementation for filaments?
Best Regards,   
73, de Pat Barthelow AA6EG  apolloeme at live.com 
        
      MOONBOUNCE                                 YURI'S NIGHT