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Vintage threads from the first ten years

Question for JD

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7/28/2000 8:21 PM
ChrisW	Question for JD Hi JD ! Can you tell us something about the screengrid-supply/resistors and the used O.T.(-impedance) ? In any case : many thanks ! Chris

7/29/2000 12:24 AM
JD	The amp I built has 470ohm screen grid resistors and a 470ohm resistor choke sub, the OT is a standard Deluxe rev, i would guess around 8k8. The plate voltage is 350v and the pre-amp tube is a EF 86 feeding a 12ax7 PI split load. 330k gridload resistors to the 6v6愀. it has lots of gain from the EF 86, maybe I will take the gain down a bit , when cranked up it is almost too much as it is now! JD

7/29/2000 10:11 AM
ChrisW	thanks JD ! Have a nice weekend ! Chris

7/28/2000 11:15 PM
eric	Re: 6v6 Tube blue gas show Thats a good siplification of the physics, now for the calculations that should be a bitch due to the duality principle for the particles.

7/29/2000 11:04 AM

Lets have a go, I don't have my notes hand so this is all from memory.

E= maximum energy of electrons = max photon energy

E=eV where in this case e is the charge on an electron and V is the plate-cathode Voltage.

E=hf where h is a constant and f is the frequency of the emitted radiation.

Therefore

eV=hf which rearranged gives f=eV/h

Sub in the values, using 400V as the plate-cathode voltage.

f=9.7 E16

converting into wavelength

=3.1 nm which is in the visible spectrum I think.

Have fun following the above

Chris

7/29/2000 8:35 PM

Actually 3.1nm is nowhere near the visible spectrum remember visible is around 600nm somwhere around there at least. I was talking about measuring the speed of an individual electron or photon without affecting its position (cant be done accurately). Makes me remember how much i hate shrodinger's equation. For some reason, i do belive that your equation is in error, but i dont have my physics book handy so ill have to look later

7/29/2000 9:18 PM
Stephen Conner	Hi Chris, I tried to torture my brain back to physics lectures and I believe you are right as to the principle. I don't know about the maths though! You're aiming for about 450nm which is the wavelength of blue light. 3.1nm is X or gamma rays or something and if you're right I'd switch that amp off NOW Steve C.

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