Anyone have experience with the Tung Sol 7581a vs. EL34, KT66, KT88, 6L6


I broke down and added another power tube (Tung Sol 7581a) to my collection.  That can get expensive as my Primaluna Dialogue HP Premium integrated has 8 power tubes.   

Why has this tube escaped me thus far?  Why is it not more popular?   Many folks don't sell this reissue tube.  

I think this is a great deal.  I was torn between the lush, thick midrange of the EL34 and the more evenly spread out sound of the KT88.  But the KT88, for all its more correct behavior didn't romance me like an EL34.  

The 7581a from Tung Sol can be had cheap and I really like them.  [I'll spare you all the audiophile terms].  They check the boxes that I was looking for. 

Does anyone have experience, information or knowledge about this splendid tube?  

PS  The next experiment is KT150s but I can't see doing it if I'm gonna lose any of that great EL34 midrange. 
128x128jbhiller
7581a tubes show more internal "blue glow" than any tube I've tried...I like it...and it illustrates my seemingly low threshold of entertainment.
Almost 2 years on with 2 x quad sets of Tung Sol 7581A in four monoblocs and they still sound superb. They've held the initial bias settings which indicates good stability and look great.  
Hey guys,  I've read your thread on the 7581a and really want to try it but I'm wondering if I can use them in my amp?  It's a Sonic Frontiers SFC-1.  The manual says it can use EL34's,6CA7's or 6550/655OA/KT88/KT90/KT99a types.  Does anyone know if I can use them and if so, what should I bias them at?  The manual says to bias EL34 at 40.  It says I can bias the others at 50.  Thanks
No clue about the bias requirements as that seems to be amp specific, but if you can use all the tubes you noted I bet the 7581a would work fine.
Thanks Guys. Think I’ll give the 7581a in my Latino ST-70. I’m thinking about also trying a inexpensive EL-34 (EH) so I can experience the supposed magic. I’ve kinda shied away from them because I am a classic rock, blues and some jazz fan and tend to like a good bass line. (I’m a drummer). So I really like a full spectrum sound which doesn’t emphasize any particular frequency range