Anyone have experience with the Tung Sol 7581a vs. EL34, KT66, KT88, 6L6

Well, I guess one could say I'm sold on the Tung-Sol 7581A.  Bought a matched quad from Tube Depot, which arrived today in good order.  All in, the cost was $210.71.  Together with the low mileage set bought in 2017 and re-installed  a few weeks ago, plus the back-up pair from Viva, with any luck I should be set for the next few years.

I would highly recommend Philips ECG JAN 7581A circa late 70’s production … Unfortunately prices have escalated of late. 

@rshak I found that too. Midband sweetness wasn’t there and they were a little tight. After 20 or so hours, they opened up. I’ve easily 1000 hours on these in my monos (2 tubes each) and they sound sublime.

no romance - when I first tried the 7581As I thought they were good - but perhaps a bit "dry" and not as warm as the KT88s.  Mind you, I last used the 7581As some years ago.  They now sound quite fine - generally well rounded and "warm" .

I mentioned earlier that two of the KT88s I had been using failed in quick succession.  They were getting longer in tooth, and I suppose their sound quality may have gradually changed, i.e., degraded, a bit towards the end of their useful life, thus making any good, fresh replacement tubes sound better.

Who can say?  I do know I'm quite happy with the 7581As now, and I may buy another pair (or even a quad) to have for the next rainy day.

@rshak So what changed from when you preferred the GL KT88s?

I bought a quad of the Tung-Sol 7581A's in 2017 when this thread started.  I used them for about a month in my PrimaLuna integrated and thought they were good, but went back to  Gold Lion KT-88s, which I had been running since since PL amp was new.

I've gone through three sets of the KT-88s in the interim, but recently had two tubes fail in as many months.  Tried to order some replacements, but found that new Gold Lions were either out of stock or, if available, had become ridiculously expensive.  So . . . I reinstalled the the 7581As and have been using them for a little over two weeks - - They sound really good - - so much so that I ordered a couple of more from Viva Tubes to serve as back-ups.  Too bad the pair costs more than the original quad  I purchased over 4 years ago, but I don't want to be without replacements if one or more of the original set craps out.

@frogman , How do you like the 7581as?  I recently sold my Primaluna and now have a Bob Carver Crimson 275, which runs (stock) KT120s.  I finally got around to trying the 7581as in it and they are really fun to listen to.  Great clarity and sweetness. 

Thanks!

@frogman Hi there. I bought mine from amazon. 8 tubes in 4 monoblocs still running fine. 

Noromance and all. Glad that I noticed this thread as it is time (again) to replace the power tubes (16!) in my Manley monoblocs and I am intrigued by your comments re the Tungsol 7581A. I have the discontinued Svetlana Winged C 6l6GC’s in them currently, but they are sounding very tired as of late. Any additional comments, especially re longevity, or recommendation of a good source would be appreciated. Amps came stock with Sovtek 5881’s and I have also gone through two sets of NOS GE 6l6GC’s. Favorites so far, the Svetlana’s, but a close call against the GE’s. 

Thanks!

Anyone try the new Tung Sol EL34B?

After a long break from the 7581a tubes, I swapped them back in.  I was using Gold Lion KT77 reissues--great tube. 

The 7581a adds a bit of the power that the KT150 has and it seemingly has more headroom.  But, I say that without checking the specs.  That's how they sound.  

I remember now why I love these tubes. 

JB, I have tried the KT150's in my previous PrimaLuna ProLogue Premium integrated and they were my favorite non-EL34 type tube. I have tried a few of the KT88 types and all of them left me wanting that warm EL34 midrange. I classify the KT77 in the EL34 category and feel the 7581A's sound more like the EL34 class than anything else. My favorite EL34 was actually a Siemens RFT from the 1970-1980's. Very nice tubes but ultimately sold them after discovering the KT77's and 7581A's. These tubes have enough of the magic EL34 midrange plus do so much more than a stock EL34 that I feel both are the ideal tube for my application. As I always say, YMMV. To each their own.

@slmccaul , I hear you!  I'm in the same boat.  Both of these are excellent power tubes, and are reasonably priced. Do you have the ability to try KT150s?  

JB, I have been flipping back and forth between the GL KT77's and the TS 7581A's for just under a year and I still can't decide which I like better. I have the same amp as you do driving my Goldenear Triton One's and both do an incredible job. I probably prefer the 7581's a little better as the GL's can sound a bit thin in certain frequency ranges, probably the upper midrange. I keep both around as I consider them both my "go to" power tubes. I find that using a softer input tube with the GL's help quite a bit whereas the TS's can sound great with most any input tube. I'm really not a fan of JJ tubes for hifi, I'm using a pair of their ECC802S long plates for input tubes and they sound fantastic. Cheap to try out too. I've been through so so many tubes to get to this point, I shouldn't even make this post as somebody will make a recommendation to me to try something new, lol. Take care.

What can go wrong is Tube Reversal Compulsion Syndrome (TRCS) where an audio geek can't decide which tubes to use resulting in socket failure and, sadly, tube abuse.

BTW,  I'll get the 7581as back in rotation again to see how they stack up to the GL KT77s.  Both are great tube compliments--I can't go wrong.

So true Wolf.  

BLASPHEMY! Human perception being the key thing in all things subjective isn't always good news or any news...or accurate news anyway. I have only 2 power tubes in my single ended Had amp so it's almost too easy to look at it and wonder, "what if I put THESE back in?" Immediately I hear differences and are those differences improvements? Sometimes clearly, other times they're simply differences that take a while to get that Oh Yeah feeling...or not.

@wolf_garcia ,  I'm sure folks could charge me with ignorance or blasphemy here--  I think the 7581as sound better with less than 1000 hours on them.  I think they fade off just a touch in my system after that.  

Don't know how much of tube listening preferences are simply about differences, but being a 7581a fan I was surprised at the "difference" when I swapped in my GL KT77s this weekend...my little amp sort of came to life. Perhaps the 7581s are getting older or something...I'm starting a log regarding tube life to avoid such issues.

Ran GL KT88s in my Cary Rocket 88 but missed the wonderful mid's of  EL34s. Rolled in a set of the Tung-Sol reissue EL34s and the magic is back. However, I purchased as my 'back-up' tube set and they are 'on-the-shelf' as I've rolled in a quad of GL KT77s, which, as stated above, are the creme-de-la-creme of EL34s. They were the 'keepers' in my previous CJ amp and same in the Cary. But, based on the theory (never disproven) that one cannot have too many tubes, I want to try a set of the reissue Tung-Sol 7581As. Failing that, I'll go with their 6L6GC-STR.

@oldhvymec Just checking that you know the thread is about replacing EL34 et al with new Tung Sol 7581A for a big improvement. 

artemus_5485 posts

Latino ST-70. I’m thinking about also trying a inexpensive EL-34 (EH) so I can experience the supposed magic.

I've heard EL34 that brought magic to the room, I've heard EL34 that made me leave the room. Don't get too cheap. You'll hear some of the worst bass and highs you ever heard. On the other hand, 6L6 like the RCAs, GOOD vintage GE are the benchmark of quality BASS and mids,
little lacking on the top, but what a GEM. Before I ever Roll power tubes, I  always check them.. I prefer to change the signature, with the signal tubes. FIRST. RCAs, Telies, Amprex or Volvos, Solvex then Mullards, everything after that may sound good, but be aware. Cheap valves can really tear up a great amp or speakers..

KT 90s are a great sounding valves, (very close to a 6550 / kt88 hybrid sound) Very clinical. I like them MUCH better than the 120 or 150s. Second they hold up forever.. Almost.

Regards

What do the 6F6G do that the TS 7581A does not do? 

Hi Just saw your post rel the 7581A. I bought a pair for my Dennis Had HO Inspire "Hot Rod" amp and really love them. I bought the amp used, it came with KT66s.

I bought the 7581 from Tung Sol and really love them, great sound - much warmer than the KT66 IMO. I also bought NOS RCA 6F6G Power Pentodes and have landed here. 

I tried the KT66, 7581, KT120 but really love the 6F6G and haven't gone back. They don't put out as much power (it seems that way) but I have high efficiency speakers and they play plenty loud for me i.e. the preamp volume control is always at 9:00 position, so the 6F6G has plenty of power for me your results may vary but I really do like the 7581A tubes - can't go wrong with them, just my 2 cents

@artemus_5 

I play drums and love the Russian Tung Sol 7851a,,.however I recently installed a quad of JJ EL34L and prefer them. They have that great midrange magic, tight punchy bass and smooth highs. The JJ's are my favorite new production power tube. They are even cheaper than the 7851a. They beat the Russian GL KT77, Mullard EL34 and Tungsol EL34B in my amp. The JJ's are a very underrated tube.

"The GL KT88 was not as good in my setup." Interesting.
I remember the 88's as dynamic in PL systems, but everyone  has different situations.

I had the 77's in my HP for a bit. Great tube. I'v kept the old RCA 6L6G's   cookin in mine for a few years now. 

I may step up and try the might 150's this year, just for audio kicks.
8@$100 each, is kind of a downer though. I've been expense free with audio nonsense for awhile.

Opening the wallet, I hear the old Foreigner song-"Feels like the first time!"

I finally tried the Gold Lion KT77s. Great tube. I think they are as good as the 7581. The GL KT88 was not as good in my setup. 

Drummer? Then you'll appreciate the new Tung Sol 7581A. Great, clean, snappy bass. Give it about 10-20 hours to sound its best.

Thanks Guys. Think I’ll give the 7581a in my Latino ST-70. I’m thinking about also trying a inexpensive EL-34 (EH) so I can experience the supposed magic. I’ve kinda shied away from them because I am a classic rock, blues and some jazz fan and tend to like a good bass line. (I’m a drummer). So I really like a full spectrum sound which doesn’t emphasize any particular frequency range

No clue about the bias requirements as that seems to be amp specific, but if you can use all the tubes you noted I bet the 7581a would work fine.

Hey guys,  I've read your thread on the 7581a and really want to try it but I'm wondering if I can use them in my amp?  It's a Sonic Frontiers SFC-1.  The manual says it can use EL34's,6CA7's or 6550/655OA/KT88/KT90/KT99a types.  Does anyone know if I can use them and if so, what should I bias them at?  The manual says to bias EL34 at 40.  It says I can bias the others at 50.  Thanks

Almost 2 years on with 2 x quad sets of Tung Sol 7581A in four monoblocs and they still sound superb. They've held the initial bias settings which indicates good stability and look great.  

7581a tubes show more internal "blue glow" than any tube I've tried...I like it...and it illustrates my seemingly low threshold of entertainment.

Speaking the modern EL34 Mullards , i only got 6 months before one died.....pretty disappointing.   I think the green label EH 34s sound better and are tough....  anyway hope the 7581a possess the goodness of EL34 and 6L6 types in one bottle!!!

Zkidd, thanks for posting.... I have a pair of Mid Monos and love them, they are awesome amps. I have had several tubes and my favorites have been KT66 and KT88 Gold Lion but I have not really had long life with them.... I had a pair of KT66 that one shorted , big fire in the bottle and it took out my midrange on my speaker..... honestly would rather that happen than amp damage..... easy fix on a Klipsch.

So in a pinch I bought a quad of Apex matched JJ EL34 locally and they actually sound quite good but I like everything I have been hearing about 7581a tubes and think I am going to order a quad.

I buy my 7581a tubes from Viva also, and only recently noticed the break-in phenomena...I haven't used any actual EL34s since my Had amp can run pretty much anything from 150s to 77s, and I have plenty of those, but yeah...I had recently bought another pair of 7581a tubes for my second Had amp, a Hot Rod version of the version I already own, and liked the sound of my original amp just a little more...until the tubes aged a little, resulting in a pretty much identical sound between the two amps...I'll likely sell one of these amps in the near future so keep your eye out for that in the A'gon tube amp sales area if anyone wants one of these things.

The new RUSSIAN production power tube to beat in my system (LTA ZOTL40 AMP) is the Tung Sol 7581a (6L6 type). Less than $100 a quad, bettered the KT77 GL, El34 Mullard and Tung Sol 34b. The KT66 is a very linear, clear, smooth sounding tube. I felt the Mullards were a bit grainy on top, I do like the GL KT77, but the 7581a are more refined overall. The issue is the 7581a need at least 150hrs of burn in for them to open up. I still need more hours on the TS EL34b to proper evaluate them. The TS EL34b are definitely smoother on top compared to the Mullards so far. I bought the 7581a from Viva Tubes. Highly recommended.

My $,02 worth here. I have a pair of Quicksilver Mid Monos that allow for me to run almost any tube that is octal based. I have used JJ KT77, TungSol KT66, TungSol 7581A, JJ and EH 6CA7, and Gold Lion KT66. To me, and this is me and my gear, the TungSol KT66 is better all around than the GL KT66 as the TungSol sounds a little less "congested" as the GL tube can to me. But the big winner here is the TungSol 7581A. As much as I love my TungSol KT66 (huge soundstage, wonderfully full and warm mids, with deep bass and tantilizing highs without the hard sound) the 7581A does all of that time 10! This is an amazing tube! I have also tried the TungSol KT120 and I keep going back to the 7581A! The Mid Monos are supposed to be about 40wpc with the 6L6 tube and its variants. Well, you sure could fool me as I feel I have a lot more power than that and my speakers are not all that efficient (87db). If you can get away with the 7581A, I would do it. Viva Tubes has matched quads for about $90, a bargain. I like the 7581 a lot more than my NOS Sylvania 6L6GC, a whole lot more, and the TungSol is not nearly as hard to get.
Okay, so that was like $.50....Sorry...

Another update...after being smitten (smote?) by Gold Lion KT77s and much preferring them to anything else in my little SE amp, I've switched to 7581As and now prefer them over the various power tubes I've stuck in this amp...including KT120s, 150s, KT88s from GL and Sovtek, and JJ (worse of the lot) and Gold Lion 77s. My tube drawer is gettin' kinda full.

alexwilds-

not many here looking for grind and compression out of their home amps.

http://fenderforum.com

I recently built a Fender Tweed Pro 5E5-A.  I put Tungsol 7581A tubes in it.  The tone is rich, chiming, well balanced - everything one could want from a Fender amp IF you like clean tones (I do, at least for this amp).  I can turn it up as loud as I dare and it is still clean and rich.   

If, on the other hand, you like grind and compression from the power tubes, go for 5881.  6L6GC split the difference. 

Update...I now consider KT120s my fave for my Dennis Had Inspire "Firebottle" HO (it's a HO...says it right there on the amp) single ended pentode amp. So there.

eh kt90 and eh 6ca7

I'm wondering if the GL KT66 hits that sweet spot everyone is wanting. Can't seem to find much feedback tho.

I did not have good life on a matched quad of Tung Sol 6L6 G big bottle tubes.   They sounded really good and looked cool , but they started to drift and one died after only a few months.   Gold Lion KT66 is a rugged sweet sounding 6l6 variennt

Have you considered the Shuguang Golden Voice KT88?

Follow up on this. I tried putting the old Raytheons back in and it was no contest. Existing attributes have consolidated initial impressions and any tiny lack of midband sweetness now seems like a more neutral clarity, if you know what I mean. Tung Sol 7581a are keepers for the moment.