The Tube Amp Doctor KT-66 is an incredible remake of the classic British tube. With its large glass envelope contoured by smooth curves tapering into a rounded brown base, the TAD KT-66 not only looks like the original, it performs like the original. This KT66 offers plenty of headroom for a thick full bodied sound with smooth yet articulate highs. The KT-66 is famously used in vintage British plexi amps and makes a great replacement for that style of amplifier and many others. The TAD KT66 is matched for both plate current and transconductance and passes all of the tests of the TAD Premium Selection process. The TAD KT-66 can be used in any KT-66 position as well as 6L6GC and 5881 amps that can supply the required 1.27A for the heater.