The key diagram is the one that shows the signal path through the amplifier. Input feeds grid, plate feeds next grid, final output is from plate. Everything else is supporting circuitry.
Note that between each stage there's a capacitor in the signal path. That's to block DC. If you want an amp that amplifies DC, each stage has to run at a higher voltage than the previous stage. The plate must be above the grid in voltage.
This was a huge headache in tube computers, both analog and digital.
Transistor circuits don't have the increasing voltage problem. Outputs and inputs are in the same voltage range. That's because transistors are current gain devices, not voltage gain devices.
> Note that between each stage there's a capacitor in the signal path. That's to block DC. If you want an amp that amplifies DC, each stage has to run at a higher voltage than the previous stage. The plate must be above the grid in voltage. This was a huge headache in tube computers, both analog and digital.
You can also stick a voltage divider (and probably some diode clamping) in there to pull the signal off of the plate down to a grid compatible voltage for the next stage if you're just doing digital computing. That was the most common setup I've seen in tube based computing. They tended to play pretty nice with the resistors needed for the plate current anyway so it wasn't that much extra RC constant delay.
It's not exactly what I'd call a rounding error, but it's manageable. But yeah, tube computing in general is an exercise in building a really fancy space heater.
I'm trying to keep my tube computer I'm building down to ~3KW, and that's probably the biggest actual constraint on design complexity.
> The key diagram is the one that shows the signal path [...] Everything else is supporting circuitry.
This is also very misleading in that all this supporting circuitry AND the stuff not even shown, such as wires routing with respect to each other and with respect to the inside or outside of a metal case ALSO contribute. All this stuff contributes to basic functionality ("noise", "hum", etc) and to finer performance (frequency response, dynamic, distortion, crosstalk, etc).
It's easy to confuse the map for the territory, the schematic for the physics of the thing. And common electronics schematics abstract away much that does matter. Engineers and builders with some experience will pay attention to this without bothering to include it in the schematic.
Pay attention when following a magazine article for example: most of the time it will point out the why of several decisions. Why they placed this and that away from each other. Why these wires are routed this way...
Transistors in principle have the same issue as tubes with bias stacking in that they only operate biased in one way and so the bias potentials necessarily add up (of course we're talking about much smaller voltages, both in absolute terms and in relation to usual supply voltages). But p-type transistors are practical, unlike p-type vacuum tubes. Well, you could build every other tube out of antimatter.
The key diagram is the one that shows the signal path through the amplifier. Input feeds grid, plate feeds next grid, final output is from plate. Everything else is supporting circuitry.
Note that between each stage there's a capacitor in the signal path. That's to block DC. If you want an amp that amplifies DC, each stage has to run at a higher voltage than the previous stage. The plate must be above the grid in voltage. This was a huge headache in tube computers, both analog and digital.
Transistor circuits don't have the increasing voltage problem. Outputs and inputs are in the same voltage range. That's because transistors are current gain devices, not voltage gain devices.