2SA1943 PNP Power Amplifier Transistor (TO-3PL)

The 2SA1943 is inseparable from its NPN partner, the 2SC5200, the two together forming a matched complementary pair that shows up by name in a huge number of published high-power audio amplifier designs favored by serious DIY hi-fi builders. Matching current and voltage ratings between the two halves ensures the push-pull output stage behaves symmetrically on both the positive and negative halves of the audio waveform, which is exactly why this specific pairing, rather than a mismatched substitute, is called out explicitly in the amplifier schematics that use it.