Tung-sol EL84/6BQ5 Due to many requests by fans of our Tung-Sol line of tubes, the Tung-Sol EL84/6BQ5 has been reissued. The Tung-Sol EL84/6BQ5 was a popular OEM tube for American-made EL84/6BQ5 guitar amplifiers, such as those built by Gibson and Harmony. Due to its rugged construction and conservative ratings, it is the most reliable current production EL84 type available for use in Vox AC-30 type amplifiers. In addition, its linearity and tone characteristic make it the ideal replacement for EL84 hi-fi amplifiers, such as those built by Fisher, Scott, and Harmon-Kardon. Strongly committed to quality manufacturing, Tung-Sol tubes have always been known for their reliability and great tone. Today's new production Tung-Sol tubes are constructed with the same commitment to quality and reliability. Tung-Sol tubes reflect the best in vintage Tung-Sol construction with unsurpassed tone and reliability.