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.
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I'm late to this party, but my experience with the TS 7581A is similar to yours....I even have the Latino VTA mods on my Dyna 70 amp, except mine are run as a pair of single chair monoblocks. I’m also coming from a set of really good GL KT66 that I liked a lot. I put in the 7581As in September, and would guess they have close to 150 hours so far.. I’ve really enjoyed the overall balance, presentation, and clarity of these tubes on my system. They’re even a bit less expensive than the GL KT66. At this point, these are my favorite of all the tubes I’ve tried in these amps. 😍😎

Another late bump here sorry. I just put a set of Tung-Sol "reissue" 7581A into Rogue ST-100 and am blown away at how full, vivid, and "classic tubey" the midrange is. A little less bass impact versus KT120, but still enough to nicely round out the sound. Rogue amps tend to have a clean, neutral & less tubey midrange (tending to dry at times) - switching to KT88 Gold Lion helps a bit here, switching into triode mode helps very little, and both of those are BLOWN AWAY by the juicy midrange effect of 7581A. Love it!!

I’m sure it’s a phenomenon caused by healthy amounts of low-order distortion, but I don’t care (good to counteract the sterilizing effect of most recording chains). It’s like getting the best of classic vintage 6L6 tube amps, but with better bass and more power. Rogue's ST100 is an ideal platform for tube rolling - individual tube bias adjustments, huge bias range, and only a quad to do.

The use of "reissue" on this tube is a a bit of a misnomer because Tung-Sol never made this tube. Its big maker was GE, and New Sensor has to roll up into their American label "Tung-Sol" because they can’t use the GE name ;)

Wow! Glad to see so many 7581 tube lovers.

@mulveling  I see you are using them in a Rogue ST-100 amp. That amp has been coming into view for me for the last 2 weeks. I thought they only used the KT 120. Its nice to learn that they use a variety of tubes. Considering it is an S'phile class A, I might have to check into this. I love amps that use a variety of tubes. Thanks

My Tung Sol 7581As have been in my Dyna/VTA monoblocks for going on 15 months now, with probably somewhere in the rough range of 500-700 hours on them.  Just wanted to reiterate how much I like these tubes in my system....there's been a little audio nirvana going on for a while.  There are new GL KT66 waiting in the wings, but it's unlikely they'll ever get installed.  I'm likely to get another set of the TS TS7581A and keep this ride going for another round. yes