Is designed a PSU with 290v-0v-290v transformer (Imax = 100mA, 58VA, Rpri=21ohms, Rsec=238ohms) and a 57mA total load. I want to have arround 350Vdc at my B+ (with silicone diode rectifier, and only 2 RC network after the B+)
I have doubts since I saw some many schematics with annotated values that let me understand that the transformer voltage might be to big. And since I am about to order it, i need some help :). I have tried the PSUD 2 method design which gives me 346Vrms
I have tried the Merlin Blencowe way with very close results http://www.valvewizard.co.uk/psu.html I found the following results Rl = 290*sqrt2/0.057 = 7195 Rs=243.2 Rs/Rl=0.0338 f * C * Rl = 50 * 47?F * 7195 = 16.9 ==> Green Curve 120% of transformer RMS Voltage ==> 1.2 * 290 = 348Vdc. Many people on told me that i should get values more close to 380VDC, far to high for a 5W amp... My conclusion is they use rule of thumb by multiplying by x1.3 the RMS transformer output which should be right with a more powerfull PT arround 200mA, but in the same time, it looks their explainations are based on personal experiences.
So how much reliable is PSUD in my context and should I consider to buy a lower voltage power transformer (10 volt less for exemple) to get 350VDC?
If you are using RC filters, you can burn off as many volts as you like in the resistors, so long as all components can stand the off-load voltage. It's much easier to lose volts than add them.
