The sound that comes from the vast majority of iPod docks is dependent on the quality of the amplifier, which can very significantly. Enter the "old, but resilient" amplification system of vacuum tubes.

The look is retro, but the sound could be much warmer than you'd get from more modern technology. And visually, it's a lot of fun: the liquid in the tubes bounce based on the volume (not the normal way they function, but an added design dimension).

Currently, this market is extremely niche, but Leonard Bellezza, co-owner of Lyric HiFi in Manhattan where they do not currently have any vacuum tube docking stations, said the accessories might soon be popular.

“Everybody has an iPod,” he said. “So anything you can attach to an iPod sells.”