[Super99]

The theory of valve amps is still very new to me, and as much as I'm trying to learn it is still very difficult for me to pick out which part of a circuit does what just by looking at the drawing.

I understand that anything that comes into contact with audio signal the capacitance is really important because it changes the signal. But is this not the case with the rest? Were power supply capacitors just specified to be as low a value as possible and still do the job? Or if you replaced 50uF smoothing and reservoir caps with 5F would it change anything else?

What about grid coupling capacitors? Do these effect the audio or are these more like power supply and just specced for cost?

Just to confirm, because it is a decoupling capacitor its value isn't as important as others in the circuit? Would 10uF be acceptable? Or is this pushing it too far?

Thanks for the help!