I don't have much to add... it is very late afterall and a lot was already covered :)
I'll throw in a few things too...
Quote:
Originally Posted by TelZilla
The fils can be traced back to the pilot light, which is "fed" by the PT @6.3V. So is this the way the cathode is able to generate current?
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Some amps don't use 6.3v lamps. A light emiting diode (LED) can also be used. Think of the square Marshall lamps when you think LEDs. Some LEDs are 6v so you can run them off of the 6.3v heater taps the PT is spitting out... others are 120v so you can run em straight off of the primary.
I sometimes use these instead of typical amp jewel lamps.
Quote:
Originally Posted by TelZilla
Pin 2 is the Control Grid, described by Aiken as "a wire mesh element located between the cathode and plate of an electron tube which controls the flow of electrons between the two elements. The control grid draws no current". I'm a little confused by this, as pin 2 looks like it's getting current (I think it's AC) from the guitar, through the input jack and the 68k resistors.
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Quote:
Originally Posted by TelZilla
So I guess my real questions are these:
~ When I pick a note, this alters the charge on the grid, which somehow sends electrons to the plate?
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Its pretty much all there... you'll get to Screen Grids a little later.
Europeans call Vaccum Tubes "Thermionic Valves." This is exactly what it is... a valve. Like your kitchen sink or garden hose. The amount you twist forward or backward on the sink controls how much water FLOW you get.
The grid is sort of the gate keeper... or garden hose valve :)
In the old days batteries were used to supply the different voltages needed by the tube's electrodes. The first set, the "A Battery" gave the heaters/filaments voltage. They were usually 2, 4, or 6 volts - so a lot of tubes' heaters were designed and built around these voltage ratings (6 still sounds awfully familiar today hehehe). The second set were usually for the Plates' voltages. These second "B Batteries" (usually a ton of little batteries coupled together) are why we still call the higher voltage feed "B+".
Imagine how heavy a Twin would be if we still used batteries??!!