me_irl

Voltage at the generation end is limited by the practical limits of insulating the windings (coils of wire in the generator that need to be close together but insulated from each other), usually top out about 25 kV for steam or gas turbines. This would usually be stepped up to 275 kV or 400 kV for long distance transmission, then back down to 33 kV for local distribution (at least in the UK).

Different solar panels generate different voltages, also depends on how they're wired together. Not sure what the big solar parks use, but much lower than a fossil fuel plant for sure. That's DC, so needs converted to AC and stepped up for transmission. Some smaller solar farms are connected straight into distribution networks.

Both power transformers and DC/AC converters do give off a bit of a hum at 50/60 Hz, but again shouldn't be anywhere close to the noise of a FF plant.