This is the most powerful audio power tube in production today. With a plate dissipation rating of 60W (compare that with the 35W of the 6550, the 42W of the KT88, and the 50W of the KT90), a pair of these KT120 tubes in push-pull configuration can deliver 150 watts or more of audio power. And when used in a vintage circuit designed for 6550 or KT88, the KT120 will deliver unbelievable amounts of clean headroom, low end rumble and dynamic punch all without overloading. The glass of this tube is a full 1/2″ taller with the internal plate structure 3/8″ longer than its nearest KT88 cousin. The internal control grid cooling fins are twice as large as the KT88 adding to the amazing performance of this tube. This particular tube draws between 100mA (.1A) and 300mA (.3A) more filament current than a standard KT88, so check with your amp manufacturer to insure you have the additional filament headroom to power these tubes. This new KT120 is the steamroller of audio tubes, prepare to be flattened.
Tung Sol KT120 power pentode tube. Made in Russia. In September of 1950 Tung-Sol introduced the 5881, an uprated and industrial version of the 6L6GA with a 23.5 watt plate dissipation, opening the doors to the hi-fi movement of the 1950s. This rugged tube also found a home in the ’59 Fender Bassman and servo amplifiers used in B-52 bombers. In 1955 Tung-Sol raised the bar of high fidelity with the introduction of the 35 watt 6550, which could deliver 100 watts with a pair in push-pull configuration. This tube was used in the Dynaco Mark III and Sunn amplifers. Today, the Russian Tung-Sol KT120 has a plate dissipation of 60 watts, making it the most powerful tube in the 6550/KT88/KT90 family. A pair of these tubes in push-pull configuration can deliver power levels of 150 or more watts. When used at the parameters found in existing 6550/KT88/KT90 circuits, the Tung-Sol KT120 is impervious to overload, delivering peak power with extreme reliability and long tube life. However, taking advantage of the higher current handling capacity of these tubes, a very unique and super powerful and stable amp can be designed using the Tung-Sol KT-120.