An apparatus and process of surface finishing golf balls prior to painting is provided. When a driving vibration is applied to the electro-mechanical energy conversion element, bending vibrations are excited in a vibration element and those bending vibrations allow out-of-plane bending vibrations to be excited in the flange-shaped elastic member. Also, the current spreads beyond a width of the ridge stripe after passing the ridge stripe and before reaching the active layer. The winding disc or the magnet disc is formed by two or more sector shaped units that are mounted to two or more support members respectively. A rigid U-shaped jaw has a pair of arms rigidly attached thereto and extending normal to the legs of the jaw adjacent the bight, the jaw being adapted to bear against a coupler attached to the end of the conduit. In addition, the capacitance multiplier includes a capacitor coupled in parallel across the cascade of current amplifiers.