6X4 EZ90 Sylvania NOS D-Getter Black Plate USA

RARE NOS VINTAGE STOCK — TESTED AND READY 💎 Premium Sylvania 6X4 / EZ90 rectifier tube, made in USA, preserved as genuine New Old Stock in original box. A highly desirable black-plate example with D-getter construction for collectors and serious tube systems. Tube Details and Codes 📌 • American tube type: 6X4 • European tube type: EZ90 • Brand: Sylvania • Made in USA • Black plate construction • D-getter design • New Old Stock, in box Testing and Performance ⚡ • Verified unused stock condition • Test-checked before listing • Clean, authentic vintage rectifier tube • Suitable for high-end tube amplifiers and restorations Sonic Signature 🎵 • Fast, stable rectification with a quiet background • Rich harmonic texture and refined power delivery • Excellent choice for collectors seeking classic American tube quality