I like the VTA mods a lot. They do have the Mk 3 and M125s in kit. Not sure how different the Mk IV is.
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.
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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Nice. I have one of the Latino VTA Dyna 70's. great little amp. I liked it so much that I bought Don Sachs Kootenay 120. Do took the design of the ST120 and customized it with the best of parts, auto bias, dual mono Power supplies, It sound great. I often wanted to try the Mk IV's. I'm surprised that VTA didn't offer that amp as a kit or assembled. |
Its my understanding that he 7581 has the same output as the KT66...that 5 extra watts. that @knotscott spoke about. One thing few have mentioned is the pretty blue light the tube emits. BTW @knotscott what "Dyna/VTA monoblocks" are you running? |
My technical tube knowledge is limited as well, but it looks like both have plate current of 54 amps with plate voltages of 350v. I’d guess the extra 5 watts is a fairly minor impact. When I switched from KT66 to the 7581A, I didn't notice any extra power....I just really liked how they sounded. More so over time, but it's subjective, and system dependent.
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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. |
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 |
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!! 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 ;) |
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. 😍😎 |
I had a Dennis Had Universal SET amp lying around that I had never really liked. But I got a new preamp with gain and I decided to bring the Had out and give it another go. I still didn't like it as well as my main set up but I had read the glowing reviews of the Tung-Sol 7581A's and they sounded like just the thing to kick the Had into higher gear and at $30ish a tube they seemed cheap enough to try. All I gain say is WOW. The 7581A's brought a ton of dynamics with strong bass and a sweet midrange and detailed highs. It sounded good enough that I decided to do some tube rolling on the 6SL7 input tube. I tried a few NOS tubes I had lying around and then decided to put in a new production Tung-Sol 6SL7. What an amazing combination. Holographic soundstage, huge dynamics, detailed with excellent everything. I'm usually very sensitive to glare and this combo had just the slightest touch of that but changing out some cables tamed that. This is an amazingly dramatic, lively presentation coming from what can't be more than an 8 watt amp. This is not a mellow, easy listening, smooth boring sound. I've tried quite a range of amplifiers and tubes and I have to say I've never heard my system sound like this. How much of that is DIY SP14 preamp I've combined with the Dennis Had/7581A/6SL7 combo I can't say yet but for anyone that likes tube rolling I say the 7581A is a must try.
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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.
If anyone actually reads this and their amp can utilize a 7581a, I just can’t recommend them highly enough. |
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 |
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. |
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 |
One week of break in. I've played 2-3 hrs every night. Some nights 4 or more. I'd guess I have at least 15 hrs on these tubes....probably 20. I still question these tubes. Everything is good except vocal placement is recessed but not all the time. Its like these tubes are hit & miss. Maybe I still don't have them burned in. I don't know. I'm not a tube guru with 50 yrs experience but I've never experienced the changes I've seen with these tubes. I think I'll put a CD on continuous play and let the amp play all day. I can see the promise of very good sound from these tubes though. So maybe I'll get a treat. |
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... |
@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. |
