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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Showing 1 response by torske

Also a big fan of the 7581a and in my PrimaLuna Dialogue HP mono amps find it to be the best match for my Sonus Faber Elipsa SE speakers.

I own and have compared many tube types in my system. Have the GL KT77’s, TungSol KT120’s, TungSol KT150’s and the stock EL34’s. 
 

KT77: very nice sound with tonal richness and good detail. In my system, there is some slight but quite noticeable bloat in the lower midrange/upper bass with these tubes. Makes rock music a little more fun due to the extra weight in the region, but overall seems to thicken and slightly obscure detail. Very musical tube.
 

KT120: not my favorite. Tonally threadbare and lack emotion. Can see why they would be impressive on a quick first audition as the bass region is tight and clean, and there is good detail retrieval, but simply lack any soul.

 

KT150: similar to the KT120’s but more enjoyable long term. Most neutral of all the tube types and very even top to bottom. They lack some of the tonal richness and saturation that the 7581a’s and the KT77’s have. Kind of remind me of good solid state sound. 

7581a: wonderful tonal richness with a very even presentation top to bottom, especially in triode mode. Great bass weight and punch without being overbearing like the KT77’s. Seems to blend the musicality of the KT77’s with some of the neutrality of the KT150’s. Just an amazing overall sound. And even better…they are the least expensive tube here.

 

If anyone actually reads this and their amp can utilize a 7581a, I just can’t recommend them highly enough.