The TELEFUNKEN Elektroakustik KT88-TK is a newly manufactured and cryogenically treated version of the legendary KT88.

The KT88-TK is a beam-power tetrode that shares similar applications as the 6L6 and EL34, and is one of the largest tubes in its class. Originally introduced by GEC in 1956, it became competition for the American-made 6550, but with the ability to handle a much higher plate voltage of up to 800 V, the KT88 became a common choice for power amplification design.

Its characteristics of high power and low distortion make it ideal for guitar amplifier applications where the user is seeking a higher gain tone with less distortion than a 6550 will provide. Tonally, the Black Diamond Series KT88-TK has the same characteristic mid-range of the original KT88 manufactured by MOV (Marconi-Osram Valve), with an expanded low end and very high end. The rigorous quality control and durable construction yields a dependable tube ready for the most demanding applications.