Great tube for Hi-Fi use
I've tried just about every current production EL34 and its variants over the past few years in my custom Bill Baker built Jolida 302B. This amp sounds just awesome with the right tubes pushing my KEF iQ90 towers. My favorite up until now was the "Winged C" EL34(I can't afford NOS power tubes!!!), but I've had two tubes out of my past two quads red plate on me. This has only happened with the "Winged Cs". I thought I'd give the JJ KT77 a try. WOW!! Glad I did!! In my rig, the KT77s are the best sounding power tubes I have tried. Soundstage grew in width and depth and these tubes are very articulate. They are very detailed without sounding the least bit harsh or hard, and they still retain that "in the flesh" 3D texture and realism of the EL34. Bass is tight and strong and highs are clean and airy. Cymbals have that nice sheen on fine recordings. VERY nice. I'll be sticking with these - they are my new favorite! Give them about 15-20 hours for them to sound their best. Highly recommended.