The 2SC1061 is a NPN Power Transistor in To-220 package. It has a DC current gain from 35 to 320 and transition frequency of 5MHz. It is commonly used in high power amplifier application along with its complementary PNP part 2SA671.
The BC546 is a high frequency NPN Transistor commonly used in low noise amplifier designs. It has a maximum gain value of 800 and a high collector to emitter voltage of 65V making it also suitable for high voltage audio amplifier applications.