Sovtek 5881 max plate dissipation?

Discussion in 'Glowing Bottle Tube Amp Forum' started by MrCoolGuy, Aug 4, 2020.

  1. MrCoolGuy

    MrCoolGuy Tele-Meister Silver Supporter

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    Hello everyone. What is the maximum plate dissipation of a Sovtek 5881wxt?
    Am I missing something on this datasheet? Groove tubes resells them as GT6L6B's...
    I've read to treat them as 6L6GC's (30 watt).
    I've read 26 watts...
    I've read 25 watts...
    I've read 23 watts like other 5881's
    Anyone know definitively?
     

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  2. archetype

    archetype Fiend of Leo's

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    All I can find is the same spec sheet you have and it says nothing about plate dissapation. Every retailer seems to have the same Sovtek marketing copy which has no useful specs, but mentions "Built to rigid military standards." If that's the case, I'd look at the internal construction to see if it's actually a new production equivalent to a 6N3C, 6N3C-E, or 6P3S Russsian tube.

    Even though the spec sheet says 250 V for plate voltage, the question/answer section of the listing on tubesandmore.com says it's 500 V maximum. They also say it's the same as a Sovtek 5881 (coin base) but with a full base. There's probably more info out there for the Sovtek 5881.
     
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  3. Rick330man

    Rick330man Tele-Afflicted

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    Do not treat the Groove Tube 6L6B version as you would a 6L6GC. It isn't in that league.

    I researched the hell out of this issue years ago. The tube sold as the Groove Tube 6L6B (5881) is not a true 6L6 or 5881, but a Soviet military servo tube (with a few variants) that specs out in the ball park of a 6L6. The best data I could put together (came across) suggested that these were conservatively rated to be 20 watt tubes. They'll take a little more, but won't hold up if you push them into 6L6GC ranges.

    If you need a 6L6GC, buy one.
     
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  4. MrCoolGuy

    MrCoolGuy Tele-Meister Silver Supporter

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    Yeah, I dont think I'm even going to use these. I have plenty of 6l6gc's that I trust. I need 5881's... and looks like I'm going to buy some old stock Tung Sols. At least they have a useable dstasheet.
    Thanks for your input, guys.
     
  5. MrCoolGuy

    MrCoolGuy Tele-Meister Silver Supporter

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    Why would Groove Tubes, a company that supposedly steps up quality control to resell good tubes, use these ambiguous Russian tubes? I don't really get it.
     
  6. archetype

    archetype Fiend of Leo's

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    NOS Tung-Sol 5881s are great tubes. You can get tested, used ones and they'll still outlast you.
     
  7. ping-ping-clicka

    ping-ping-clicka Friend of Leo's Ad Free Member

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    contact Josh Scott of JHS Pedals he owns a bunch of Sovtek amps
     
  8. tubegeek

    tubegeek Friend of Leo's

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    Because they are current production maybe. Keeping the ol' supply chain in business.
     
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  9. Rick330man

    Rick330man Tele-Afflicted

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    Personally, I use JAN Philips 6L6WGBs in my Hot Rod Deluxe. When I need a 6L6GC - like in my Sunn T50C amps - I use some old SED 6L6GCs.
     
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  10. Dacious

    Dacious Poster Extraordinaire

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    The 5881s if you use them will produce slightly lower power - they're actually quite rugged but not too many people are enthralled by the tone they produce. They suit some amps more than others. A set came in my old 70 watt Pro Reverb and were still in it when I sold it a couple years later.
     
  11. radiocaster

    radiocaster Poster Extraordinaire

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    20.5W according to a Soviet datasheet for the 6P3S-E.
    6p3s.gif
    It's the "20,5" in the second section towards the bottom, the maximum ratings, Sovtek never put out this information on their datasheets, but it's essentially the same tube.
     
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  12. MrCoolGuy

    MrCoolGuy Tele-Meister Silver Supporter

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    I actually have noticed a change in tone with these tubes (whether or not they are a true 5881). I was trying them in a tweed bassman clone where I previously used some old RCA 6L6GC's. They lack the low end and clarity... or something hard to describe compared to the GC's.
    I don't like them. I was trying to get my bassman as close to original spec as possible... I think I'm going to try some old Tung Sol 5881's (like I believe 5f6a's came with). If I don't like those either, back to the 6L6GC's.
     
  13. Dacious

    Dacious Poster Extraordinaire

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    Yes, that was the complaint - they tended to be 'brown' sounding, not in a good way. Muddy and lacking sparkle. They did suit some things like Tremoluxes and Bandmasters I believe but don't quote me. Also the more modern Bassmans they can lower headroom and add a bit of grind.
     
  14. MrCoolGuy

    MrCoolGuy Tele-Meister Silver Supporter

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    They do seem to offer a bit more grind, obviously... but to me that's the last thing a bassman needs. The preamp is hot enough.
    I was just surprised at the difference in low end. I usually don't have to turn up the bass control much. But now I hesitate to purchase some good old stock 5881's... I don't want them if this is how they sound.
     
    Last edited: Aug 5, 2020
  15. Dacious

    Dacious Poster Extraordinaire

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    No - the Sovs as someone noted aren't really 5881s. Good vintage ones OTOH should sound great.
     
  16. archetype

    archetype Fiend of Leo's

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    Fender's schematics for narrow-panel 5F6 and 5F6-A Bassman amps specify 5881 tubes.

    If you're trying to achieve an 'original' tone with your Bassman, then don't mess with the Russian tubes that don't adhere to the data sheet specs of a US-made 5881.

    The NOS Tung-Sol 5881 will get you closest to the orginal tone. A Philips 6L6WGB is a 5881 with a different designation and should have a bit more definition to the tone, compared to the Tung-Sol. Bought used, either of those tubes will still outlast you and me.

    The 6L6GC may be the more defined and brighter tone that suits you. Original spec is 5881 and will generally be a bit fatter and softer tone when cranked up loud.
     
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  17. ThermionicScott

    ThermionicScott Poster Extraordinaire

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    All of the above could be true, depending on application. That's the fun of vacuum tube ratings! :)

    If you're trying to keep an old Russian airplane in the air, run those tubes as cool as you can. But if you want the sound of tubes working really hard and don't mind replacing them every couple months, let 'er rip! Especially if the amp isn't leaving your basement these days... sigh.


    (FWIW, in my amps, none of which run high voltages, I treat these as 23W tubes.)
     
    Last edited: Aug 5, 2020
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  18. Rick330man

    Rick330man Tele-Afflicted

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    The JAN Philips 6L6WGB is the tube the U.S. military went to after the original Tung Sol stopped producing their 5881. The 6L6WGB is the best sounding power tube I have ever used in my Hot Rod Deluxes.

    Just in case someone does not know, the modern production tube sold as Tung Sol is a current-production, Russian made tube. It is not the original product that so many tone enthusiasts prize.
     
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  19. schmee

    schmee Doctor of Teleocity Silver Supporter

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    I've been going through tubes to sell, I found these tubes. They seem a lot like the old Tung Sol 5881's that came in Bassman heads etc. Some 6L6wgb's are labeled as 5881's but they have small bottles. These tubes I have have larger bottles, but not as large as some 6L6GC size bottles. They seem a bit like the real deal old Tung Sol 5881's. These are labeled Sylvanias though. Wonder what they really are?
    [​IMG]
     
  20. ThermionicScott

    ThermionicScott Poster Extraordinaire

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    I can see what looks like a date code on the middle tube. Are there any other codes that you can find, perhaps on the base?
     
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