Music enthusiasts will tell you there's nothing quite like "tube sound", the warm, rich sound quality that old vacuum tube amplifiers bring to the music played through them. And they'll pay top dollar for it! Once considered obsolete, vintage vacuum tube amps now sell at a premium, because audiophiles want to reproduce the harmonic distortions this old tech is so famous for. This now-beloved distortion was initially seen as a bug, not a featur...