Dual Rectifier With E34L, Which Bias Mode?

Discussion in 'Gear & Equipment' started by Kyle-Vick, Dec 7, 2017 at 9:05 AM.

  1. Kyle-Vick

    Kyle-Vick SS.org Regular

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    Last week I picked up a Rev G, 2 channel Dual Rec. I decided to try out the tube rectifiers and found out one was toast, as it popped the fuse. When checking that out, I noticed the previous owner has put JJ E34L tubes in it and he has the bias switch set to 6l6. Does anyone have any experience with these, should I keep it in the 6l6 setting?
     
  2. cwhitey2

    cwhitey2 BlackendCrust Metalâ„¢

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    Ummm....there is a BIAS switch for a reason :lol:

    Anyways I think the difference is plate voltage, I could be mistaken but I think el34 require more then 6l6's.

    I ran el34s in mine and used the el34 switch.
     
  3. Kyle-Vick

    Kyle-Vick SS.org Regular

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    These are JJ E34L, not EL34; so I am not sure if they are different than normal EL34 and need to be run in the colder setting.
     
  4. mnemonic

    mnemonic Custom User Title

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    Check out eurotubes.com, Bob has a ton of stuff written about different tubes in rectos as well as kits of all different types.

    Depending on the current draw (I think) you may have to have the bias switch in a different setting than what you might think.

    From the last time I read through his site, I think some settings (potentially tube recto setting?) shouldn't be used with certain tube sets and bias settings.

    Just as another wrench in the works, not all recto's are biased the same. Depending on the year it may be hotter or colder. I imagine Bob should know though.
     
  5. vanhendrix

    vanhendrix SS.org Regular

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    I run my E34Ls in EL34 mode, seems to work fine.

    I really like the sound of regular EL34s, but my recto says not to run them with the silicon diodes (apparently not all rectos are like this?), as you can tell the bias gets too hot and they start to get kindof a "raygun" sound to them. That's why I ended up getting the E34Ls in the first place, so that I could use the diodes.
     
  6. cGoEcYk

    cGoEcYk SS.org Regular

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    I have a set of JJ EL34L's and run them in EL34 mode. I liked them and will probably explore in more detail at some point.

    My current setup is 6550's (35-40mA range) in 6L6 mode.
     
  7. Kyle-Vick

    Kyle-Vick SS.org Regular

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    Is the EL34L the same as the E34L?
     
  8. cwhitey2

    cwhitey2 BlackendCrust Metalâ„¢

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    Sorry, I miss read that!

    e34l's have an even higher plate voltage the el34's so there should not be any issues. Just don't run 6l6 run el34 mode :lol:
     
  9. Kyle-Vick

    Kyle-Vick SS.org Regular

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    No problem man, I read the tubes as EL34 at first haha. So with the higher plate voltage, I want to stick to the cooler 6l6 setting, correct?
     
  10. vanhendrix

    vanhendrix SS.org Regular

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    Run the E34Ls in the EL34 mode.

    From eurotubes:
    "These amps are fixed bias with no adjustment other than the switch to go between EL34 mode and 6L6 mode. 6L6GC's, KT66's and KT88's are run in the 6L6 mode. EL34's, 6V6S's, E34L's, KT77's and 6CA7's are run in the EL34 mode."

    Further reading: https://www.eurotubes.com/store/pc/mesa boogie amps.htm
     
  11. Kyle-Vick

    Kyle-Vick SS.org Regular

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    Awesome, thank you! I must have missed that when I was reading it over earlier. I was rushing to read it at lunch, so no surprise there.
     
  12. neotronic

    neotronic SS.org Regular

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    nvm
     
    Last edited: Dec 7, 2017 at 5:35 PM
  13. vick1000

    vick1000 SS.org Regular

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    EL34 mode. They stress the grid resistors and PT more than EL34s or 6L6s, but a Mesa should handle them well. Keep it in tube rectifier mode if you are worried.
     

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