Popular Alternative to EL-34 Tubes. Subsitute these for EL34 tubes to achieve greater clean headroom and less compression. Harmonically rich, they sound very full and detailed wiht nice bass clarity. Some refer to this a a "Super EL34" - this could be attributed to the fact that the KT77 tends to have a higher current draw than normal EL34 tubes. "KT" stands for kinkless triode as this tube has no kink in the curve of the sine wave.
You are purchasing a MATCHED QUAD of tubes (x4 tubes total). Brand New in original packging.
NOTE: If the kit includes more than one POWER TUBE, then they (the power tubes) will be APEX Matched. NOTE: Some tube Acronyms are interchangeable - for instance: 12AX7 is the same thing as ECC83; 12AT7 = ECC81; GZ34 = 5AR4. There are others, but these are the most notable.