What is going on here with this grounded cathode stage?

[Windcrest77]

The primary purpose is to define the plate load at AC. Without it, in this circuit, the plate load is 44K and the cathode load is 22K. This does not work as a phase splitter, as it delivers double the voltage swing from the plate that it does from the cathode. QED

Ultimate source: Radio Dwsigner's Handbook.

In your mind… envision it as an RC unit. It must not be envisioned as a 'resistor from which one can analyze it without the capacitor'. Both, or nothing at all.

Indeed, once you take both imaginarily out of circuit… connecting the 22 kΩ anode load to B+ directly, and the 22 kΩ cathode 'load' to ground, it becomes an obvious 'simple' phase inverter. Insertion of the RC pair substantially alters the power supply B+ quality, by filtering out whatever 'crud' is on the B+ rail, be that power supply ripple, crud from other stages, picked up RF (external or internal!) or what-have-you. It is solid engineering for a vexing problem, especially for circuits which are point-to-point wired with common 'economically feasible' wiring.

The only real reason I'm going on and on about this, in this way is because once you come to view the RC pair as a pair and a single tunable circuit element, viewing other circuits with the R and C perhaps quite distantly placed on a diagram becomes so much easier.

⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
⋅-=≡ GoatGuy ✓ ≡=-⋅

I think I'm beginning to understand the C2 main purpose, and side-benefits, here as best I can, considering a year ago I didn't know AC and DC can travel on the same wire and I couldnt spell cathodyne. Thanks.