Tung-Sol 7581A......Wow!!


So, after seeing a few posts about the 7581a I figured I had to try them in my Bob Latino ST-70. Besides, I needed new tubes and I like something different. That's the fun of tubes....well, at least partially.  I installed them and it took some time to run them in. They still may not be run in. I probably only have about 15 hrs on them. The first day was spent hoping they would get better. They did. They are getting there slowly. I'm coming from GL KT-66. These are different. Very promising but the emphasis is completely different than the KT66. I heard some details which I hadn't heard before, yet it was in the lower mids /upper low frequencies. Kind of surprising since the KT66 has great bass. But the 7581 has cleaner bass. I could tell from the beginning that dynamics are a strong suit of the 7581. And the more I play, the more the dynamics expand...and expand. The dynamic range now is stunning....maybe even too much at times. My system is very resolving. I listen mostly to classic rock where the  dynamics
are really emphasized especially by lead guitar.  But the great volume swing makes the  guitar often sound very bright.  I've played in rock bands most of my life (Drummer/vocalist) so I know what live music sounds  like. There is an over emphasis on the dynamics with these 7581a's. I have not heard anything with a wider dynamic range than I experienced last night as I played Molly Hatchet LP. The lead guitarist sounded as if he was playing a hot guitar with a hot amp and an overdrive pedal. I  am amazed at the dynamic range...even though it is over extended IMO. Its kinda like a freak of nature. OTOH, I really like these tubes. Detail and tone are very good but more subtle than the 66's. My wife loves them, though she agrees that they get close to being too bright I can see where these tubes are great for less aggressive music. Not sure about classic rock. Then too, most of it sounds pretty doggone  good........well, until the dynamics grab you and hurl you against the wall (-:. I'm hoping that the dynamics will ease off some. maybe I'll try some classical music and see what the dynamics do. I have the 1812 Overture on Telarc. But that might knock the walls down. Oh well, I just had to tell someone about it. FWIW, I've read nothing by anyone else in pointing out an extended dynamic range. And because everything is so system dependent, I suspect it will ease off with mine.
128x128artemus_5
with my gear the 7581A does not sound "bright" at all but provides more tonal body and weight without loss of transparency or compressing the soundstage. I swing between these and the Gold Lion KT77s, which are more neutral tonally top to bottom.
@tuberist

I read 2 threads about these tubes and most everyone  said something similar to what you have said. And I am overall satisfied because I think it is the dynamics which are causing  what appears as brightness. And its just that one part in the song,  not the whole song. Actually, I'm surprised at how much change these tubes have gone through. I've never had any tubes which changed sound as much as these, But  I also see all the good qualities you spoke of about the tubes as well. 
I switch my tubes around here and there and found that the 7581As are a great tube in my little single ended pentode amp...and the blue glow is cool...GL KT77s however do get some serious amp time as there's a hard to describe dynamic in those tubes that holds up well, where the 7581s seem more neutral maybe...damn...maybe I'll put them back in my amp and prove myself wrong...again...
@wolf_garcia 

I had been switching back & forth from Gold Lion KT-66 to the Russian 6p3se/6n3ce. The 6p3se sounded similar to the KT-66. Great bargain IMO. Yeah, gotta love that blue glow.