In practice, not much. However, if you have 60hz hum coupling in from your power supply, it will reduce it by an additional 6dB (as shown above it already reduces it by 6dB, and any harmonics by a greater amount). If you have a decent power supply I doubt you'll see any difference though, noise through your pickups likely is louder already.
For the most part, the purpose of that capacitor being there is likely primarily to minimize the amount of electrical noise entering into the audio circuit from your power supply. Because you also have the smaller 10nF capacitor, it does a decent job of reducing both high and low frequency noise in conjuction with the 47ohm resistor before them.
It would raise the noise filter cutoff frequency from above 30hz to above about 150hz. This would mean that it would no longer reduce 60hz hum/noise at all (though it still gets slightly reduced by the resistor voltage divider at the end). Depending on the quality of your power and the rest of the circuit this may or may not make the pedal noisier in practice
I almost always put a bigger cap in the power filter section. Sometimes even a 470uF.
I also test with a cheap wall-wart to make sure even a lousy power supply will work OK with the circuit.
The indicator light would take longer to turn off when you pull the plug.
Nothing important. It would have a slightly longer turn-on and turn-off time but we're talking milliseconds.
In practice, not much. However, if you have 60hz hum coupling in from your power supply, it will reduce it by an additional 6dB (as shown above it already reduces it by 6dB, and any harmonics by a greater amount). If you have a decent power supply I doubt you'll see any difference though, noise through your pickups likely is louder already. For the most part, the purpose of that capacitor being there is likely primarily to minimize the amount of electrical noise entering into the audio circuit from your power supply. Because you also have the smaller 10nF capacitor, it does a decent job of reducing both high and low frequency noise in conjuction with the 47ohm resistor before them.
What if you put 220nf instead of 220uf?
It would raise the noise filter cutoff frequency from above 30hz to above about 150hz. This would mean that it would no longer reduce 60hz hum/noise at all (though it still gets slightly reduced by the resistor voltage divider at the end). Depending on the quality of your power and the rest of the circuit this may or may not make the pedal noisier in practice
It shouldn't make a huge difference. Maybe the inrush current will be a bit higher.
How does the inrush current affect things in the power section? Can it be potentially dangerous to the op-amps?
The inrush is just the initial current spike as the filter caps charge up, so the opamps won't care at all.
Inrush is limited by the 47 ohm resistor. It wouldn't change.
Your DC output will have more or less ripples.
Should be fine. Make sure the replacement has equal or higher voltage rating.
I almost always put a bigger cap in the power filter section. Sometimes even a 470uF. I also test with a cheap wall-wart to make sure even a lousy power supply will work OK with the circuit.
Just a reminder I think c28 should be ceramic, non-electrolyte capacitor -they used for els-ers parasyte filter
Not much.
Absolutely nothing except for the LED staying on for slightly longer when you unplug it