I need some math help about PS math

[kagliostro]

You know I've no study on the matter and so many things are difficult to me

I refer to this old tread

http://www.el34world.com/Forum/index.php?topic=6712.0

Quote from PRR

300V/0.7A= 435 ohms.

Vacuum tubes are several-K ohm devices. No small number of vacuum tubes can fully use a 435 ohm supply.

Staying at 300V, you need a primary impedance near 800 ohms to suck 0.7A DC at full power. That's 200 ohms per side. You want a tube with Rp(triode) less than 200 ohms. EL34, 6550, etc are over 600 ohms. So you need at least three pairs.

I really would like to go more inside this thing

Please have you further explanations and/or a link where I can read about the connection between Voltage, Current, Resistance of the PS and the OT specs and the choice of the Output Tube/s?

Many thanks

K

[twbranch]

Ohms law: E is voltage, I is amps, R is resistance in ohm. E = I X R or Voltage = Amps X resistance. Another way to read this is R = V/I which is the quotation you have there. Google Ohm's Law for more in depth explanation.

Regards

[kagliostro]

Thanks Twbranch

I wasn't considering Ohm's Law as to be of primary importance also for this argument, I was completely absent-minded

Meanwhile I remembered that HBP pointed to me to the NEETS, I've give a look to those modules

and I've find the module n. 6, about electronic emission, tubes and power supply

I hope to find there something that can help me to fix better on my mind all this matter

http://www.compatt.com/Tutorials/NEETS/New_PDF/14178A.pdf

I've downloaded it and I'm going to read

K