1. Single lithium battery or USB power supply is suitable, also can use four sections of 1.5V battery, if use with the transformer power supply,it must add 5V voltage circuit, more than 6V will burn IC out.
2. + and - of power supply can't be reversed, power supply voltage can't be more than 6V, otherwise it will damage the IC.
3. there were high gain buffers, can't change any board device parameters, do not accord with the parameters of the IC will lead to damage.
4. input wire please use shielding wire, can rise anti-interference function, eliminate clutter current sound.
5. output is CMOS BTL drive mode,4 wire is completely independent, don't connect together!