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Modern Tung-Sol 7581a Tubes

The new Tung-sol KT66 draws 0.9A heater current. Thus the claims that it is a big bottle 6L6GC and the same as their 7581A. So they should be go to go in any 6L6GC/7581A circuit.

The Gold Lion KT66 draws 1.3A. A quad of these will draw quite a bit of extra current.

I haven't listened to the T-S but have used the GL in two amps. They sound very, very good. Lots of punch and openness. Not as warm as some EL34 types.
 
JonL said:
Any reviews of these TS 7581a in Fender guitar amps?
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I know this is an old thread, but I use only 7581As in my Fender amps. I have the old ones (Philips and like. For a while, Peavey was relabeling them, so I have a few of those as well), but I hear the TS variants are fairly close. Given that they are rated at 5,000 hours MTBF, I figure I'm set for life.

I also have a quad for my MC30s and they have put everything else to shame, including Mac branded GE tubes.
 
IMHO if your amp can handle the GLKT 66- go with them.
No contest sound wise between the TS7581A and the GL’s.
You save a few pennies, but you lose it sound wise
 
The Tung Sol 7581A is one of my favorite power tubes. I'm thankful for a great functioning and sounding 6L6GC type tube in current production at a reasonable price. I own the GE, Philips and Tung Sol 7581A. I have owned most of the 6L6GCs except the RCA black plates. My favorite of them was the Philips/Sylvania 6L6GC with the dual getters. Never tried a 5881.

I always choose the Philips 7581A or the Tung Sol 7581A for my amplifiers. I use the Philips 7581A in a Mesa Boogie Mark III and Peavey 5150. Just sounds the best and I guess it's because it was designed around the Philips 6L6GC. I use the Tung Sol 7581A in a Mesa Boogie Rectifier. Peanut butter and jelly. The classic rectifier tones are 6L6GC. The best rectifier tones are 7581A.

I find the Tung Sol 7581A to have a balanced and clear sound with greater headroom and frequency extension than a 6L6GC.
 
It’s been relatively easy to find black plate rca singles. Just leave out the words black plate on your search and you’ll get lucky every once in a while. Definitely the best sounding I’ve tried with exception of maybe genalex (depending on if you want British tone or American).

Come to think of it the el37 is a good mix of the two styles. Nice and dynamic and open but reserved on certain subjects.
 
pjrengineer said:
It’s been relatively easy to find black plate rca singles. Just leave out the words black plate on your search and you’ll get lucky every once in a while. Definitely the best sounding I’ve tried with exception of maybe genalex (depending on if you want British tone or American).

Come to think of it the el37 is a good mix of the two styles. Nice and dynamic and open but reserved on certain subjects.
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A little context :) Two of 6l6GC guitar amps are fixed bias/sextet and another fixed bias/quad. Gets expensive putting together NOS sets! Have you tried a Philips 7581A compared to the RCA and if so what did you think?
 
I haven’t tried 7581 yet but did try their 6l6gc and they sound relatively comparable to a grey plate ge with maybe slightly less glassy sound. Both great tubes.

I don’t worry as much about matching power tubes as I make sure the input / pre tubes meet distortion levels on my fixed bias amps. I’m not usually over driving them or near 70 percent even so….but yeah you’d need a lot.
 
pjrengineer said:
I haven’t tried 7581 yet but did try their 6l6gc and they sound relatively comparable to a grey plate ge with maybe slightly less glassy sound. Both great tubes.

I don’t worry as much about matching power tubes as I make sure the input / pre tubes meet distortion levels on my fixed bias amps. I’m not usually over driving them or near 70 percent even so….but yeah you’d need a lot.
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I think the Tung Sol 7581A is the best of modern 6L6GC types and it can hold it's own with anything NOS. Has a little more headroom, frequency extension and the frequencies seem more balanced compared to 6L6GC.

Dug myself a few bad holes with fixed bias/sextet/NOS power tubes and I'd rather just warn people before they feel a lot of pain.
 
After popping in my idle quad of TS 7581A, they are a very dynamic and rich and harmonic sounding tube.
And well balanced-esp compared to 6L6/GC's.
Nice wide soundstage.
They have a little more pop then the KT66's for sure.
Which by they way-take 100+ hours to break-in bass wise.
(Ironically-IMHO much better sounding tube then the GL KT88)
The GL-has a more holographic character to it, but is a more polite tube than the TS7581A.
Really hard to find any faults with the 7581A.
I purchased them quite a few years ago, when doing some major system changes-and forgot how really good they are.
They aren't KT88's (My fav tubes-Shuguang GEC/MoV clones, or EH KT88), but I could easily and happy live with them.
And the GL KT66's.
 
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Stopped rolling tubes
GL KT66, GE 6189W followers, Gold Lion 12AU7 gains, and Gold Lion NP in both preamps
I'll use the TS7581A's when I want a change.
Thing is these KT66, really no need to-they do everything great.
As Upscale point out-they seem to be a exceptional match to Primaluna Amps.
 
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Tungsol 7581A also gets my vote. I've been running them in my Quad II amps in the place of GEC KT66. In terms of their sonic qualities they are on par with the old GECs.
 
Treyphan said:
So I recently purchased a Quad of Tung-Sol 7581a tubes.
After seeing a few glowing reviews, from “so-called” modern tube “haters”. I figured for the cheap price....why not?

I’m a Big 6L6 amp guy. So I had plenty of amps to try them in. I’m usually a Vintage NOS tube guy only, if I’m buying them. However, with Tube Prices getting out of this world, especially on 6L6GC tubes. I decided it was worth the, relatively small cost as a test.

I received them about 2 weeks ago, and have over 100 hours on them now. So they are certainly “broken in”, if you believe in that. Not looking to make this a thread about that.

Anyway. First amp I tried them in was a Stromberg Carlson ASR-444/Stereo 60. (Accepts 7027/6L6/etc)This is a wonderful 30 watt stereo amp, that I recently COMPLETELY restored. I love it. It originally ran a Quad of RCA 7027a’s, which are still measuring nearly NOS and that I love. Anyway, I couldn’t believe my ears once the TS 7581a’s were installed. Pure bliss. Nice across the entire Freq Range and just great. The bass seemed a bit tighter, with a very nice mid, not too scooped as is common with 6L6 variants...still supple and nice though.
Next I tossed a set in one of myMC240’s. Wow. I’d removed a Perfect quad of RCA Blackplates to try the TS. Some stiff competition. Well I loved the sound, so much so I ordered a second quad for my other 240. I run a Strapped setup in my main system. Using 2 MC240’s feeding some Bozak Concert Grands. Theyve never been happier. Even with Blackplates.

I’ve got TONS of 6L6 variants. GE Grey plate’s, RCA Blackplates, Sylvania STR’s, RCA 7027a’s, Couple quads of various Sovteks, GE 7581, and more. So I feel I’m pretty versed in this particular tube family.

I kept waiting for the TS 7581a’s to let me down....and they just DIDNT.

I couldn’t be happier. I’ve got no affiliation with TS or anyone selling them. Just thought I’d mention it and people could maybe try for themselves. Now don’t get me wrong, they are not perfect, and I wouldn’t give my Vintage tubes up for them. It’s just with some of the 6L6 variants becoming quite expensive. Maybe this would help someone.

Also, I’ve read a few posts, all around the web, not here. That have people doubting the validity of the TS 7581a. It’s not just a re-badged 6L6. These are real deal 7581a with 35w plate dissipation. Built well, and sound great.

Hey, try for yourself, don’t take my word for it. Get em while they are hot! Glad to see these and many other Modern tubes really starting to be competition for the Old school stuff. Cause those ain’t gonna last forever.

Enjoy everyone! Hope this helps even 1 person.
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this is good to know. thx for the informative post.
 
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