A tube in my amp recently gave up the ghost. It was one of the four KT88 tubes in the amplifier stage. I’d never changed tubes in the three years I’ve had this amp, changing just one tube was a bit risky and not very coherent in technical and sonic terms, so I decided to change the four original Cayin tubes. I had no reference or possible comparison with other tubes and I wanted to try something different, both in terms of tube type and brand. I replaced the four KT88 tubes with a matched Electro Harmonix EL34 quad. And what a surprise, a completely different listening experience. The first thing that struck me was the increased, or lengthened, reverb that emerges, smoothing out the soundstage without exaggeration and amplifying the musicians presence, particularly in an acoustic context and studio recording. This is striking on Thad Jones The Magnificent Thad Jones, where the trumpet floats elegantly in the Van Gelder Studio and the drums envelops the band. The double bass, which I expected to be in the background, is in fact well present and balanced. The medium register is warm, and Barry Harris’s piano certainly comes into its own. One might think that this amp behaviour would be annoying in another musical context, such as electronic music, especially when listening to Surgeons Girl’s A Violet Sleep, but what’s interesting and surprising is that reverb is only magnified when it’s already present in a recording, not when it’s non-existent. There’s no fake addition, just a sense that everything is working in the direction of the music.