Volume Vs. Tube Life

Discussion in 'Marshall Amps' started by BrentD, Dec 20, 2017.

  1. BrentD

    BrentD Active Member

    Joined:
    Jan 27, 2012
    Messages:
    594
    Likes Received:
    246
    Trying to make this hypotehtical, but I find my JTM sounds best with the channel volumes at 6/7 and 4. This is natural overdrive territory but I wouldn't consider it "cranked."

    We've all heard that running amps flat-out burns tubes faster than running them turned way down. But what about in the middle? Is it a linear relationship? Aside from anomalous tube failures, when is it no longer safe to just run the tubes that are in there? Is it best to change them at regular intervals (every year, every other year, etc.)?
     
    liontato likes this.
  2. johan.b

    johan.b Well-Known Member

    Joined:
    Feb 21, 2015
    Messages:
    2,103
    Likes Received:
    2,879
    Location:
    Södertälje, Sweden
    Most people bias their tubes at 65-70% of max dissipation...so even at idle, with no sound, you're burning away tube life.. with signal, the tube will be off 30-40% of the time... don't worry about it.. there are new tubes to be bought and if you don't want to run them as intended, you might as well play solid state.
    J
     
  3. Crunchifyable

    Crunchifyable Well-Known Member

    Joined:
    Oct 28, 2011
    Messages:
    693
    Likes Received:
    372
    Location:
    Georgialina, USA
    It depends on how you feel about the money for tubes and the stress on the other components.

    A master volume might save you money in the long run. And your hearing if you aren't attenuating.

    It sounds like a very loud volume, above band volume maybe. But on some amps, you just gotta crank em up for the magic.

    It's safe but the tubes aren't going to last forever. I think an amp that never sees volume can have the tubes last indefinitely (decades or more). If you're playing it at gigging volumes (or above) then maybe 6months to 2 years based on hours of use. You may know it when they are worn out, or you may not.
     
    liontato, BrentD and Len like this.
  4. Jr Deluxe

    Jr Deluxe Well-Known Member

    Joined:
    Sep 12, 2017
    Messages:
    274
    Likes Received:
    277
    Fenders are biased very cold like 50% mdp. Tubes have lasted for decades in some old fenderz. even played loud. EL34s arent known as durable tubes and people like to push them to get that marshall drive. That burns the tubes up in say 600 hours. Back the bias off to about the low 60s to make your tubes last longer. Moderate volume in the middle range like between 3 and 7 probably doesnt hurt the tube life one bit. Its winding out plexis biased hot that kills tubes. If you jam a couplr hours every night on a wound out plexi be prepared to change tubes about every 6 months.
     
    BrentD and Crunchifyable like this.
  5. tschrama

    tschrama Well-Known Member

    Joined:
    May 15, 2010
    Messages:
    1,475
    Likes Received:
    770
    Location:
    Netherlands
    +1 on Johan. b

    Read up on the website of Randall Aiken tech section 'why bias at 70%'.

    in short... cranking an amp make life easy on the tubes..allthough counter intuitive..
     
    BrentD likes this.
  6. tschrama

    tschrama Well-Known Member

    Joined:
    May 15, 2010
    Messages:
    1,475
    Likes Received:
    770
    Location:
    Netherlands
  7. Jr Deluxe

    Jr Deluxe Well-Known Member

    Joined:
    Sep 12, 2017
    Messages:
    274
    Likes Received:
    277
    BrentD likes this.
  8. Jethro Rocker

    Jethro Rocker Well-Known Member

    Joined:
    Mar 11, 2011
    Messages:
    10,259
    Likes Received:
    15,791
    Location:
    Saskatoon, Canada
    Given the generally average tube life of 5000 to 10000 hours, which can be found in many places, it would take years to burn up a set of tubes. To kill a set in 2 years would be about 7 hours a day even at the lower end of tube life spectrum.

    Just play 'em.
     
    Rokinroller and BrentD like this.
  9. Crunchifyable

    Crunchifyable Well-Known Member

    Joined:
    Oct 28, 2011
    Messages:
    693
    Likes Received:
    372
    Location:
    Georgialina, USA
    Not just Fender...Mesa...Peavey...Traynor (Yorkville sound era), etc, are well known to be biased cold. Not necessarily 50%, but enough to have crossover distortion. Which is another topic.

    But suffice to say there is merit to the idea that cold bias makes tubes last longer.
     
    BrentD likes this.
  10. Jr Deluxe

    Jr Deluxe Well-Known Member

    Joined:
    Sep 12, 2017
    Messages:
    274
    Likes Received:
    277
    True dat. And just for the record i posted that many fenders are found biased around 50%. My personal recomendation was for the low 60s. My 4104 is about 65% . It sounds good there so i left it there. When it gets hot it probably drifts up to 70%. If you bias higher than 70% what happens when your tubes get hot? You drift into territory i dont want my old amps going into.
     
    BrentD likes this.
  11. JeffMcLeod

    JeffMcLeod Well-Known Member Gold Supporting Member

    Joined:
    Sep 28, 2017
    Messages:
    2,137
    Likes Received:
    3,479
    Don't bias your tubes to get more life out of them, bias your tubes to get the sound you want. If they last 5 years, so be it. If they last 5 months, so be it. You got the sound you want.

    If you're trying to avoid spending money on new tubes, this forum has a Classified section down towards the bottom. I'm sure your JTM will sell in no time.
     
  12. BrentD

    BrentD Active Member

    Joined:
    Jan 27, 2012
    Messages:
    594
    Likes Received:
    246
    Ouch! Really, I'm just asking in the abstract because people don't seem to play these on "5" - it's either bedroom volume or all the way up. Curiosity made me wonder what happens in the middle.

    :cheers:

    P.S. - It is a bigger issue if people play to failure and the tube takes out other components with it.
     
    MonstersOfTheMidway likes this.
  13. danfrank

    danfrank Well-Known Member

    Joined:
    Mar 5, 2015
    Messages:
    1,012
    Likes Received:
    566
    Where'd you get those numbers?!? In my experience, no way... I'd say 1000-2000 hours, especially for power tubes; and that is probably being on the optimistic side.
     
  14. Jethro Rocker

    Jethro Rocker Well-Known Member

    Joined:
    Mar 11, 2011
    Messages:
    10,259
    Likes Received:
    15,791
    Location:
    Saskatoon, Canada
    I saw something on here the other day quoting Randall Smith. Others too. Seems to be in the 5000 hrs for power tubes. Obviously mileage varies.

    At 1000 hrs, it's still an hour and a half EVERY day for 2 years to kill a set. I'll look for the other thread. If you play out for 3 hours every 2 weeks and practice for 2 twice a week, it still gives you all of 4 years.
    Here's from a Hughes and Kettner blog

    "You can expect a conventional amplifier tube to have a service life ranging up to 10,000 hours."

    http://blog.hughes-and-kettner.com/does-it-pay-to-regularly-swap-tubes/
     
    Last edited: Dec 20, 2017
  15. tschrama

    tschrama Well-Known Member

    Joined:
    May 15, 2010
    Messages:
    1,475
    Likes Received:
    770
    Location:
    Netherlands
    5000 to 20.000 hours.. quoting Peter Diezel
     
    Jethro Rocker likes this.
  16. tschrama

    tschrama Well-Known Member

    Joined:
    May 15, 2010
    Messages:
    1,475
    Likes Received:
    770
    Location:
    Netherlands
    read the Randall Aiken paper... then you ll know what happens in tje middle.
     
  17. Jethro Rocker

    Jethro Rocker Well-Known Member

    Joined:
    Mar 11, 2011
    Messages:
    10,259
    Likes Received:
    15,791
    Location:
    Saskatoon, Canada
    Even if its 2000 or 3000, that's an ass load of playing. I certainly wouldn't regularly change mine at a certain age.
     
  18. spacerocker

    spacerocker Well-Known Member

    Joined:
    Feb 6, 2009
    Messages:
    1,761
    Likes Received:
    1,354
    Location:
    UK
    People worry far to much about valve life, in my opinion, and replace them unnecessarily....

    I've seen 10,000 hours quoted for an EL34, but even if it was half this, assuming you play for (say) 4 hours a week, practices and gigs, that gives you 24 years!

    I think this is about right. I have a 1980 2203 still on its original valves (pre-amp and power), and a 2009 JVM410 with original power valves, but I only ever use either of these amps for full band practices or gigs. (At home I use an AVT20 through a 4 x 12 Cab, which gives a better sound for home practice anyway!)
     
    Rokinroller and Jethro Rocker like this.
  19. Jr Deluxe

    Jr Deluxe Well-Known Member

    Joined:
    Sep 12, 2017
    Messages:
    274
    Likes Received:
    277
  20. danfrank

    danfrank Well-Known Member

    Joined:
    Mar 5, 2015
    Messages:
    1,012
    Likes Received:
    566
    Yes, I agree with you on this. Even 1000 hours, like you calculated it above, is a long time of use.
     
    Jethro Rocker likes this.

Share This Page