Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kagliostro on January 08, 2013, 02:45:19 am
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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 (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
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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
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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 (http://www.compatt.com/Tutorials/NEETS/New_PDF/14178A.pdf)
I've downloaded it and I'm going to read
K