Basic grounding question

[demonstratedspatulas]

I know I learned about all this years ago, but picking up amp building again now and I just can't remember.

When doing grounding, I have generally done things in a linear fashion, flowing straight from stage 1, stage 2, stage 3, cathode follower, PI, power amp, finally ending up at the negative terminal of the reservoir caps for the plate supply.

(As opposed to running individual ground wires from each gain stage or section back to the negative terminal of the reservoir caps, which if I remember correctly is called star grounding?)

First question is: Is it preferable to do linear grounding or star grounding? When choosing the correct grounding scheme, the payoff is lower noise level, is that correct? Or preventing parasitic oscillations? Or something else?

Second question: If it's ok to do a linear style grounding like I described above, how is grounding handled with the panel controls? Could I run a second wire along the panel that grounds things from the input controls, through the tone stack, vol, and presence, finally terminating at the negative terminal of the reservoir caps? Or, should I run one wire from each panel control region back to the relevant stage? ie, for a gain pot, should I run a wire from the CCW of the pot to the bottom of the cathode resistor of the 2nd gain stage?

Third question: I remember reading at some point that you are absolutely not supposed to use pot casing and the chassis for signal grounding, the only single wire that should ever touch the chassis is the earth terminal at the IEC inlet. Can you confirm this as correct? I just can't remember at this point.

[pdf64]

Merlin’s covered it all http://www.valvewizard.co.uk/Grounding.pdf
The chassis safety ground should have its own dedicated connection and fastener.
It’s a different thing to the amp’s 0V arrangement, and any connection between that and the chassis.