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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

Showing 9 responses by wolf_garcia

wolf_garcia
6,626 posts
 
Don't know how much of tube listening preferences are simply about differences, but being a 7581a fan I was surprised at the "difference" when I swapped in my GL KT77s this weekend...my little amp sort of came to life. Perhaps the 7581s are getting older or something...I'm starting a log regarding tube life to avoid such issues.

wolf_garcia
6,626 posts
 
BLASPHEMY! Human perception being the key thing in all things subjective isn't always good news or any news...or accurate news anyway. I have only 2 power tubes in my single ended Had amp so it's almost too easy to look at it and wonder, "what if I put THESE back in?" Immediately I hear differences and are those differences improvements? Sometimes clearly, other times they're simply differences that take a while to get that Oh Yeah feeling...or not.
wolf_garcia
6,626 posts
 
What can go wrong is Tube Reversal Compulsion Syndrome (TRCS) where an audio geek can't decide which tubes to use resulting in socket failure and, sadly, tube abuse.
wolf_garcia
6,626 posts
 
I bought a pair of new JJ KT77s and they didn't sound as full and clear as the supplied Gold Lion KT88s or the Sovtek KT88s currently in use in my Dennis Had "Fire Bottle" SEP amp.. Are the Gold Lion KT77s simply better tubes? If so, I'd be willing to check em out…I tried the JJs with various rectifiers to see if there was some synergy issue, but went back to the 88s. Still, curious.
wolf_garcia
6,626 posts
 
Update...I now consider KT120s my fave for my Dennis Had Inspire "Firebottle" HO (it's a HO...says it right there on the amp) single ended pentode amp. So there.
wolf_garcia
6,626 posts
 
Another update...after being smitten (smote?) by Gold Lion KT77s and much preferring them to anything else in my little SE amp, I've switched to 7581As and now prefer them over the various power tubes I've stuck in this amp...including KT120s, 150s, KT88s from GL and Sovtek, and JJ (worse of the lot) and Gold Lion 77s. My tube drawer is gettin' kinda full.
wolf_garcia
6,626 posts
 
I buy my 7581a tubes from Viva also, and only recently noticed the break-in phenomena...I haven't used any actual EL34s since my Had amp can run pretty much anything from 150s to 77s, and I have plenty of those, but yeah...I had recently bought another pair of 7581a tubes for my second Had amp, a Hot Rod version of the version I already own, and liked the sound of my original amp just a little more...until the tubes aged a little, resulting in a pretty much identical sound between the two amps...I'll likely sell one of these amps in the near future so keep your eye out for that in the A'gon tube amp sales area if anyone wants one of these things.
wolf_garcia
6,626 posts
 
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.
wolf_garcia
6,626 posts
 
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.
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