The Tung-Sol EL84/6BQ5 tube gained popularity as an OEM tube in American made amplifiers such as those built by Gibson and Harmony. Today, this Tung-Sol makes for the most reliable current production EL84 type available for use in Vox AC-30 amplifiers. This tube also works as an ideal replacement for EL84 hi-fi amplifiers like those built by Scott, Fisher, and Harmon-Kardon.