....another hour, another question... My 5e3 pre-built chassis has a 230v Primary PT, as such everything is running *slighty* hot on 240v mains. The tube plates are ok as per other thread, and I am happy with them and the tube dissipation numbers I have. .... but the 6v6/12a.7 filaments are running at 6.9v and the 5y3 rectifier at 5.4v - just about in spec, but I would be more comfortable with them a bit lower. I would like to bring them down to 6.3v / 5v and am planning on putting the right resistors in series as per advice around and instructions on @robrob pages. I've worked out the values for the drop and the right wattage but all the example I can find are done on the 6.3 power/pre tube heater circuits. Can I do this for the 5v 5y3 filament circuit as well ? ie find the right resistance for the drop required then get two resistors of half that value and put them in series on both sides of the ac feed to the 5y3 ? Does it being carried on the high end of the HT affect this in any way ?