Vacuum tubes have been around for ages, and for better or worse, they have their advocates for use in amplifiers and preamps. However, tubes are simply inconvenient devices. Even a 12AX7 preamp tube ...

This one is a superior class AB push-pull configuration tube amplifier project delivering 80 Watt RMS per channel. Four 6550 high power tetrode vacuum tubes in triode mode and class AB2 push-pull ...