tda2030, using source of simple feeding, for potency of 14 watts with a source of 15 volts. That source should be with transformer, rectificators and good filter capacitors, there is not need of regulated source. for protection of the circuit to use a fuse of 3 amperes in the line of +b of the amplifier. Use a heat-sink of heat in the circuit integrated tda2030. See the datasheet of the tda 2030 to know which heat-sink to use. That integrated it is cheaply and easy to find at the market. For a version in bridge for until 28 watts@14v and version using symmetrical source sees the datasheet of the tda2030. That circuit can be fed by car batteries by good time without needing to recharge her. The tda2030 is usually found as amplifier of stage of potency of systems of home theater, it is in those that promise 1000 Watts of potency. For now a tda2030 supplies 14 watts, then 5 tda2030 supplies less than 100 watts rms. But that is a good idea, to use the tda2030 as amplifier of potency of systems surround, for the subwoofer the ideal is an assembly in bridge for more potency.