12V is the convenience option for wall plugs. Currently using +-5V, according to the coil impedance. This also give option to change LDO output with resistor if needed. I should note that this is a fixed metal detector for school project instead of handheld.
Other than that, I have being bench PSU and its drawing 0.5A at 1kHz on both rails. Current sensing reading was a lot more than what was shown on the bench PSU, but was in fact internally limited to audio amp.
Audio amp is limited to 3A, LDO 1.5A while this may never reached, I just design it for the sake of technical limits.