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Really...My favorite power tube is reissue that's not widely popular

If you run 6l6/EL34 variants, I HIGHLY recommend trying this tube out.  The Tung Sol 7581A reissue.  I've had these for a good bit of time and compared them against KT150s, EL34s (several brands), KT88s, and maybe another that I'm forgetting.  They are a mere $30 a pop and they are the best tube I have heard. I know that's a brave bold statement to make as there is so much competition out there and the tube is very much under the radar from what I can tell.  

After having these around for a long time (and in and out of the amp), I had them in and was nearly spellbound one night by how great they sounded upon reentry into my amp.  I did a search and could only find one review, which I agree wholeheartedly with.  You can find it here: https://wallofsound.ca/audioreviews/amplification/6l6-vacuum-tube-review-tubes-courtesy-of-www-thetu...

I am nearly incredulous there isn't hype out there about this tube.  Simply my favorite tube.  I thought I'd pass this along as it may be much cheaper to give them a whirl then fuss with a much more expensive power cord, cable, or other tweak.  
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Showing 5 responses by mulveling

mulveling's avatar
mulveling
1,774 posts
 
I wasn’t even aware there was a vintage Tung-Sol 7581A to "reissue". Obviously New Sensor / EH doesn’t have rights to the Philips / Sylvania, RCA, or GE names, so perhaps they just pick their "Tung-Sol" label as the go-to for reissues of power tubes mostly associated with American makes.

Around 10 years ago I ran a restored pair of Heathkit W5 monoblocks with 1960’s GE 7581A side-getters & "flesh" colored bases (into Tannoy Kensington SE), and there was definitely some magic there. Wonderful tone, holographic 3D image. I later had the amps re-fitted to Gold Lion reissue KT66, which sounded more powerful and dynamic, but lost some of the "magic" tone and 3D imaging. The GE tubes looked to be exceptionally well made - the Russian "re-issues" look ugly but I realize that may have no bearing on sound quality. I think I still have some of them, but my fancy new amps only take KT88 and up, 8 at a time (or my old amps which can take the 7581A, but freakin’ TWELVE at a time) :(
mulveling's avatar
mulveling
1,774 posts
 
@noromance
Eicos are awesome too! I had an HF-87 with the most incredible vintage tube amp tone (it was even a good tone with cheapo EH EL34, but better with Mullard XF2/3/4 and a bright-ish 12AX7 to balance, e.g. Japanese). Small sound stage though - but I know they have mono amps that can do much much better. Heard a pair of HF-22 once, and loved them!
mulveling's avatar
mulveling
1,774 posts
 
@soundermn 
A vintage 7581A should be closest to a 6L6GC, and then to KT66. It's not really "that" close to an EL34, but according to Prima Luna's manual the EL34 setting is your best choice available and should work fine though it will somewhat reduce the power output available from the amp. I wouldn't expect the power reduction to be TOO much; maybe say 30%?
mulveling's avatar
mulveling
1,774 posts
 
@soundermn 
Awesome, glad you found out your favorite tube and personal nirvana, even if it was with the original EL34! Funny, I tried KT150 in my own amps (VAC 200iQ) earlier this year, and like your case they came in dead LAST of 3 sets - versus Tung-Sol KT120 and Gold Lion KT88 reissue, in my case. The bottom end was VERY powerful, dynamic, and punchy, but in the end it just swamped the music and sounded unbalanced. Sounds like my amps were really designed for KT88, but the KT120 are similar enough and actually eek into the #1 spot for my tastes. The KT150 just sound like a different species compared to those two, but I realize they might be amazing in amps designed specifically for them.
mulveling's avatar
mulveling
1,774 posts
 

Would the 7581A be biased the same as a 6L6GC/KT-66? I am currently running KT-88s in my DeHavilland 50A mono blocks and would like to try the 7581As. The DeHavilland is designed to accept 6L6/KT-66 tubes and a bias setting for those is specified in the owners manual. Would it be safe to assume that the same bias setting be used for the 7581A?

I'm not a tech but NO I would not assume that. I was running Heathkit W5 monos originally with NOS GE 7581A. When I switched to reissue Gold Lion KT66, those ran a LOT hotter and my tech had to adjust the bias down so they wouldn't orange-plate. 

Of course you're talking reissue Tung-Sol 7581A which I haven't quite tried yet, but I do have three quads on the way to try in my Rogue Apollo Dark monoblocks :) 

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