Sovtek EL84 Matched Power Tubes Soft Duet EL84 Matched Power Tubes Soft Duet The Sovtek EL84 series of power tubes produce an unbeatable smooth, warm, distortion Excellent replacements in vintage VOX AC-30's and the like, our EL84's are used by Fender, Crate, and Peavey These are Sovtek EL84 tubes in platinum matched sets Their platinum matching process consists of a 24-hour tube burn-in period followed by a bias (plate) current measurement in milliamps