Nice to talk with you today on 40 meters Don. I build step start into everything, as I use solid state rectifiers, and often go over 50 UF.
I am not sure if the mercury vapor things hold up better or worse then the solid state stuff under short term overloads. I am not fond of MV, warm up time, filament transformers needed, they take up lots of space, toxic waste, etc... Brett N2DTS > > > This is a choke input with two 4 mf in parallel across the > output and > > somewhere it seemed to imply that the step start was only > needed for cap > > input. > > > > As far as I can get with the heavy math, it seems like the resistor > > required would only be a few watts as it is only dealing > with the 100k > > bleeder as a load. > > > > I'm not sure how much plate voltage and current you plan to > run from the > power supply, but it has been my experience with loads on the > order of > 2000-2500 volts at 600-700 mills or so, you don't have to > worry about the > need for step-start with choke input filter using a swinging > choke, until > you go beyond 25 mfd of filter capacitance. > > My 8005 rig runs at 1300 volts on the plate, with total drain > from final, > modulator and audio driver plus bleeder resistor, somewhere > in the vicinity > of 700-800 mills. I use a 52 mfd filter with no step start without a > problem. The filter choke in that rig is non-swinging, 10 > Henries @ 1 amp. > The p-p 845 audio driver stage stays on all the time and > pulls about 150 > mills, acting as extra bleeder, holding the voltage steady > even for cw > operation. Add the steady 320 ma drain from the final during > AM operation, > and the plate voltage is very stable during modulation, which > keeps the > class-B modulator stage happy. > > Don k4kyv > > ______________________________________________________________ > AMRadio mailing list > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Partner Website: http://www.amfone.net > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > ______________________________________________________________ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
