2 for two different transistor pcb printed circuit crafted case you can use the appropriate Transistor 2N3055 and MJ2955 Used in metal sheath version TIP3055 and the plastic-type metal-sheathed version is more powerful than TIP2955 size and structure, but... Electronics Projects, RMS 50W Hi-Fi Amplifier Circuit "audio amplifier circuits, transistor amplifier, " Date 2019/08/01