alt Hacker News> I have found better ADC chips than the ones that come pre-soldered on most EDP32 dev boards (and have breadboarded them up with success).
Depending on your setup: beware of your ground and realize that breadboards are an extremely bad fit for this sort of application. It's hard enough to get maximum performance out of a good DAC on a custom designed PCB, on a breadboard it can be a nightmare.
The breadboard has validated the communication between the ESP32 and ADC chip (over I2C).
It's enough that I've now moved to KiCad layout and will wait for the boards to come back to see if the actual ADC data I am getting is more or less linear, noiseless…