Single-core copper power cord is good.

1. The single-core copper power cord is used on CD players because it has strong tensile strength, is not easy to break, has strong resistance to surge current, and is easy to shape. Multi-core copper wire has poor flexibility, poor break resistance, poor skin resistance, and poor heat dissipation.

2. When used in CD player power cords, multi-core copper power cords have poor tensile strength, are prone to mold breakage, have poor surge current resistance, and are inconvenient for shaping. The single-core copper power cord has good flexibility, good heat dissipation, good skin resistance, and good break resistance.