KT77 Tetrode Vacuum Tube

The KT77 is the GEC/MOV true pentode equivalent to the EL34, sharing the same pinout and similar operating characteristics but with subtly different sonic properties. It was developed as a higher-reliability, higher-linearity alternative to the EL34 for professional and industrial applications. The KT77 tends to offer slightly tighter bass and more extended treble than a typical EL34 while retaining the midrange richness of the pentode topology. Original GEC production was limited and commands high prices; the Gold Lion reissue by New Sensor is the primary current production source and is well-regarded.