AD1 ULTRON 4A28 RE604 4683 TAD1 P15/250 VALVE TRIODE DHT FINAL POWER AUDIO AMPLIFICATION NOS (?) 100%

This genuine AD1 ULTRON made in Belgium is NEW NOS even without box. Aesthetically it looks a lot like the Tugsram P15/250 but structurally and different in several respects. In particular, the suspension of the filaments is much more robust and with springs all in one direction, the BLACK plate is slightly larger as well as the glass bulb. The AD1 is, like the 2A3 and other very famous DHT tubes with direct heating, a highly linear Triode and suitable for low frequency AUDIO amplification. European base B8A. The AD1 was produced by the most important tube manufacturers in the world: Telefunken, Valvo, Tesla, TeKaDe, Philips with the same name or equivalent. This AD1 ULTRON, very RARE today, is practically NOS (no original box), perfect condition! Upper mica at full circumference, V-shaped tungsten filament suspended by 4 strong and shiny springs, inverted cup getter in the base, which is completely firm with the bulb. Ideal for use as a driver for high power triodes or in push-pull as a power amplifier for AUDIO amplification. The AD1 is undoubtedly the Triode with the best sound qualities. 100% test, full emission, no gas, no short; Rarity!

EQUIVALENT: P15/250 = 4683 = AD1/350 (more powerful) = PX4A = KL72406 = T460 = 4XP = TAD1 = RE604 S30c = AD1n