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 ...

Most audio tube amps we see use common tubes – usually a 12AX7 for the preamp and one of the more common power tubes such as an EL34.[Daniel], on the other hand, decided to build his own audio tube ...