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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
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artemus_5 OP
1,917 posts
 
OK, so I let the amp run several hours yesterday before listening last night. Bottom line, no strange noises last night. Everything come together nicely. I do believe these tubes are burnt in now. Sounds good.
artemus_5's avatar
artemus_5 OP
1,917 posts
 
OK, I'm here to cap off this mini review of the Tung-Sol 7581A. Though a roller coaster ride prior to being run in, these are  well balanced tubes. If there is a frequency range which dominates the other, it may be the midrange though both high & low frequencies are well represented. They are smooth top to bottom. However,my system is very revealing . My speakers are well known for their midrange clarity. And so, I wonder if this hot midrange is as a product of tubes & speakers which display midrange better than most? Also I am a drummer who cherishes bass and eschews midrange. So I may be more midrange sensitive than others. Whatever the case, everything has settled in now and I find no offense. I would recommend these tubes with one caveat...Patience will be rewarded with a good balance of music
wolf_garcia
6,681 posts
 
For reasons perhaps too subtle to accurately describe in any meaningful way, I’ve been sticking with GL KT77s for months now as they seem to (here I go) be more dynamic or...uh...something...than the 7581a tubes which I weirdly simply got bored with. I get a coherent and dynamic sound from my 12wpc (or something) little Had amp and Klipsch Heresy IIIs, and am also a drum freak...Bill Stewart’s "Band Menu" is a nice example of proper (meaning you clearly hear everything he’s doing) drum sound to my ears. Another great recording is a one-off from a band I saw a couple of times named Vorcja (album is "Maximalist") where Keith Jarrett’s son Gabe Jarrett is a monster drummer.
artemus_5's avatar
artemus_5 OP
1,917 posts
 
I think I learned of my midrange "disdain"(?) in the 70’s when Graphic equalizers were the "in" thing. I always made a nice smiley with the 5 band. I couldn’t imagine the mid above the 0 (neutral).   I really like a good bass line and then too, playing so tight and closely with the bass may have something to do with my lack of mids. I hear midrange fine. and play off it too. 

I also remember having to change it when I had the band practice house. We’d play a recording of the song we wanted to do and the guitarist would most often point out the midrange lack. Sounded fine to me. 

I have heard very good things about the GL KT77. I had the 66’s and was very happy with them. I might have to give the 77’s a try. It is nice to have an amp where so many different tubes can be used
torske
1 posts
 

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.

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