6BG6GA for a 6l6GC - too good to be true?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Mickey_C, Dec 16, 2003.

  1. Mickey_C

    Mickey_C The Original Racketeer Gold Supporting Member

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    Has anybody seen this:

    http://www.vacuumtubes.com/6BG6.html

    These are apparently tubes manufactured by Philips, that have the same components as the 7581A. From searching online, it would appear that the plates are even the higher dissipation plates, and philips did it to save money. They sell for a whopping 6.00 each, which if they sound like a Philips 6l6GC then this is a GODSEND. Looking at the pictures online you have to admit, they even look like the same NOS tube, other than the plate cap.

    You put this adapter thingy in your socket that puts the plate voltage to the cap. The adapter is 5.00.

    The NOS Philips 6l6GC/7581 is about 90.00 per pair.

    Somebody slap me please, I need to know if this pipe dream is really a nightmare.
     
  2. Fretts

    Fretts Member

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    I looked at the site and I see what you mean. Interesting!
    Personally, I don't like 7581s, I think they sound nasty, but the only problems I see are practical ones. Between the required adaptor, and the addition of the terminal on the top of the tube, plus the connector, you will be adding a lot of height to the assembly, raising the question of Will It Fit? If it fits, do you like the sound? Doesn't look like it would cost too much to find out.
    I would go for it and see how it sounds, and I hope you will report your findings.
     
  3. DreamTone7

    DreamTone7 Guest

    I like the 7581As in Fender Twins (BF). Those tubes are hard to beat for keeping the bottom tight and the top sparkling. I understand that they are military-grade STR387s (both being made by Sylvania). This would mean they are great in Boogies as well....which had OTs designed around the STR387. These subs should sound close if not spot on. I'd be interested to hear any comparisons if you try them. They're a lot cheaper and easier to find than a good quartet of 7581As.
     
  4. Mickey_C

    Mickey_C The Original Racketeer Gold Supporting Member

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    I guess this does bring up one further problem.

    The tubes in a Vibro-King are bottom hangers - I wonder how secure they will be with the adapter and plate cap. The tube retainers grip the tube base (standard fender style), which in this case would assure me that the 5.00 adapter wouldn't shake loose when the tube dives, smashing against the alnico hub of the speaker, and providing 465 volts where The God never intended it.

    Solutions?

    If they sounded great, I guess I could just rewire the bases, and add the plate cap leads right from the chassis.

    They would have to sound divine for that. Lord Valve highly recommends the 7581 - says it is the best quantity NOS currently available, far better than any Russion 6l6GC.

    At 6.00 per tube, I would plan on buying about 15 sets (if they are awesome). At that price, it is pretty tempting.
     
  5. Mickey_C

    Mickey_C The Original Racketeer Gold Supporting Member

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    I ordered a matched pair and the adapters for 26.00.

    I guess I will find out how they work. I must be crazy... but I will post the results.
     
  6. scottl

    scottl Member

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    The good vintage Svetlana's are $27 for a matched duet at KCANOS. These are in no way a bad tube. Many like the tone more than 7581's. I just replaced my Philips 7581A's with Svets in my Fuchs. Just for the hell of it. I'll report back, but so far, I think they sound as good or better.

    Many people think the Svet's have the closest tone to Blackplates. I would spent 13.50 over the 11 for these hybrids (including adaptor that needs to be assembled). Just my 2c.

    I suppose that for those that prefer the Philips this is a great deal provided they are the same. Seems kind of hoky and questionable based on the source. This site cators to audiophiles and who knows how these will act in a guitar amp w/ vibrations and a different design.

    Caveat emptor.

    Scott
     
  7. scottl

    scottl Member

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    Eh... Matter of opinion there. No offense against the Lord, but I have a set of Philips 7581A's and Svetlana 6l6's. I would not say that the Philips are far better. In fact, the Svets may be a little fuller sounding. My understanding is that Svets may have a reduced life expectancy versus the Philips. The tone of the Svets is generally considered to be excellent. I am in the process of tone testing as I type :)

    Scott
     
  8. Mickey_C

    Mickey_C The Original Racketeer Gold Supporting Member

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    The Philips 7581A and 6l6GC wants to biased on the hot side, as per what I read online. Like in the order of 50ma. The more I have read, these are not really JAN 7581A equivalents, they are Philips 6L6GC equivalents. They are not military spec., but a 6x6Gx equivalent - which means the top plate brother of the 6L6GC. Better for me! The 6L6GC has gotten decent enough reviews:

    http://www.thetubestore.com/6l6costello.html

    The RCA Blackplate is supposed to be better sounding - and I wouldn't doubt it judging by the prices. They are also recommended on the VK group. If I were a rich man, there would be no contest.

    The Svetlana's are supposed to be good too, but from what I have read are not a match to the Philips (when biased right), and as you mentioned, shorter tube life.

    Of course none of this is per my experience, just information gleaned online from forums and newsgroups. So I would highly recommend ignoring me (at least for now). LOL.

    The adapters are a one time expense. If I truly dig on them, I could add a switch to the chassis to select the tube type, and add the plate lead (which would also shut off when not selected). I would have to dig them a lot to do that to my Vibro-King. But it would make it able to accept either tube natively.

    I guess I don't mind being a guinea pig for the low cost tryout. What can it hurt?

    (Famous last words, you guys can inscribe them on my tombstone when the lead shakes off and the 465volts hits the speaker, and kills me. LOL.)
     
  9. DreamTone7

    DreamTone7 Guest

    From my experience, it just depends what you want. The 7581A can handle more power and has greater headroom than the RCA. The Svetlana IS a good tube....somewhere between the RCA and the 7581A in tone; but it does have a much shorter life-span than either of the NOS tubes. So if you prefer the RCA, you will probably prefer the Svet over the 7581A....tonewise. If you prefer the 7581A you will again, probably prefer the Svet over the RCA. Just be aware of the the Svet limitations in terms of life expectancy. I use both RCAs and 7581As....just depends on the amp and what I am trying to do with it. FWIW, the 7581A is the same as the STR387 6L6GC....but with extra mica spacers for ruggedness. Tonewise, you'd be hard pressed to hear a difference between the two. They're both made by Sylvania. My bet is that these subs will sound like the 7581As.
     
  10. slide man

    slide man Member

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    I have bought quite a few tubes from SND tubes and always been happy with them. He does cater to audiophiles and can not answer question about guitar amplifiers. However he does know tubes and only sells the real thing.

    Slide Man
     
  11. Blue Strat

    Blue Strat Member

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    For that price, I would just try them. Since there's absolutely NO consensus on tone, getting positive or negative reviews from 100 sources does not mean that you'll agree (trust me, I've shipped over 7500 tube orders). Besides, different amps "like" different tubes.
     
  12. mbruffey

    mbruffey Supporting Member

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    I ordered the 6BG6's with two adaptors from Mike and made up the adaptors at home. Mike's instructions for making the adaptors are more than sufficient, even for someone like myself who never made one before. They sound just like I would expect a Philips 7581A to sound, in my BF Twin Custom 15 RI. These easily fit, the "top" cap is plenty tight, and the sound is quite impressive. They were very well-matched from Mike, in addition. Lots of solid bass and lots of highs. Mid's seem nearly to drop out, in this amp--I play an L5 Studio (clean/Chet) with Lindy Fralin's pulled to single coil. IMHO, these really are just as good as the Philips 7581A for 8 bucks each, matched, plus enough 5 dollar adaptors for as many slots as you need. Try 'em! All that said, I still prefer the Sylvania 6L6GC Short Bottles for my style in this amp--more mids. Wanna trade? LMark
     

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