The KT88 is an electron tube in the execution as Strahlpentode or beam -power tetrode ( octal ) with about 19 ​​W output power (Po) and a maximum anode dissipation of 42 W. The tube is rarely used in amplifiers for electric guitars. One of the few amplifiers, which is already equipped at manufacture with KT88 tubes, the Marshall JCM800 " Kerry King" Signature Head ( 2203KK ). In tube amplifiers for electric bass or hi-fi tube amps but the KT88 is more commonly in use. The pin assignment is the same as a 6L6.

The KT88 was introduced first time in 1956 by General Electric Company (GEC ) as a larger version of the KT66. Licensed production were brought by Marconi Osram, IEC / Mullard and Genalex by the company as a Gold Lion at the market. Today, the tube from the Chinese company Shuguang, JJ Electronics will (formerly Tesla) and JSC Svetlana made ​​.