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Pictorial of Biasing a Marshall Jubilee.

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  • #31
    Re: Pictorial of Biasing a Marshall Jubilee.

    As always, great info GJ!

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    • #32
      Re: Pictorial of Biasing a Marshall Jubilee.

      bump for vault
      Epiphone Dot (Seth/Seth)
      Fender Hybrid Telecaster (APTR-1/JD)
      Peavy Predator (aps2)
      Squier Standard Jazz Bass
      Seagull S6 CW Mahogany w/ L.R Biggs Duet II

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      • #33
        Re: Pictorial of Biasing a Marshall Jubilee.

        This thread must be banned...in the vault
        Originally posted by Guitarist
        Honestly, I like Scott's words. "There is a rhythm to life. Ride the waves."

        And keep in mind that while nothing lasts forever, nothing is lost.
        http://soundcloud.com/adrian-czarnecki/tracks

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        • #34
          Re: Pictorial of Biasing a Marshall Jubilee.

          Originally posted by Gearjoneser View Post
          Next, I put the bias tool in between a power tube and the amp, turned on my meter, and noticed that the bias was on the cold side after a couple years of using it lightly.....it read 29mA. EL-34's and E-34L's usually sound best between 35 - 42mA.

          My method is to have the amp chassis plugged up with the cab and guitar, and hit some chords, while adjusting the bias pot. I hold the chassis up on an angle with my meter laying on a transformer. I'm EXTREMELY careful to not electrocute myself by using a plastic handled screwdriver, and I protect the cab by laying a towel on it. I always bias by ear, trying to get the amp to sound as punchy and strong as possible, but make sure the numbers fall between 35-42mA.
          know what it should be for EL84s dude? extra bonus points, thanks for the cool photos

          tom

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          • #35
            Re: Pictorial of Biasing a Marshall Jubilee.

            Originally posted by Gearjoneser View Post
            Bias tools come in the mA or voltage versions. I like the mA version better, so if you shop for one, buy the mA tester. I think I paid about $15 for it.
            This is definitely headed to the vault, once we've finished it.

            Joe...

            Why do you prefer the mA version? The mV ones are the ones with a 1-Ohm shunt resistor installed, right? I'm just wondering why one would be better than the other.

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            • #36
              Re: Pictorial of Biasing a Marshall Jubilee.

              Originally posted by Simon_F View Post
              This is definitely headed to the vault, once we've finished it.

              Joe...

              Why do you prefer the mA version? The mV ones are the ones with a 1-Ohm shunt resistor installed, right? I'm just wondering why one would be better than the other.
              What are these units called? I'd like to check out if there are any on ebay.de

              I don't have to buy a multimeter and a bias probe then!
              Originally posted by Guitarist
              Honestly, I like Scott's words. "There is a rhythm to life. Ride the waves."

              And keep in mind that while nothing lasts forever, nothing is lost.
              http://soundcloud.com/adrian-czarnecki/tracks

              Comment


              • #37
                Re: Pictorial of Biasing a Marshall Jubilee.

                Originally posted by StrangeSound View Post
                What are these units called? I'd like to check out if there are any on ebay.de

                I don't have to buy a multimeter and a bias probe then!
                Look under "tube bias" or "amp bias" and you should find them. BUT you still need a multimeter for it to plug into.
                Epiphone Dot (Seth/Seth)
                Fender Hybrid Telecaster (APTR-1/JD)
                Peavy Predator (aps2)
                Squier Standard Jazz Bass
                Seagull S6 CW Mahogany w/ L.R Biggs Duet II

                Comment


                • #38
                  Re: Pictorial of Biasing a Marshall Jubilee.

                  Originally posted by Simon_F View Post
                  Why do you prefer the mA version? The mV ones are the ones with a 1-Ohm shunt resistor installed, right? I'm just wondering why one would be better than the other.
                  I like the mA version because I like to know how hard the tube is getting hit with current. The Voltage Bias Tool is just fine, but by knowing the amperage (mA), I can tell if those plates are going to heat up too much or not.

                  Before I put the chassis back in the cabinet, I like to use it for the evening and observe the glow of the tubes and listen carefully to the tone. Once I know it's sounding better than ever and the plates aren't turning orange at all, then I put the amp back together, and it's good to go for a year or two.

                  This Jubilee is not my main amp. I just play it regularly at home and don't put too many hours on it, so those JJ E-34L's should last 5 years.....maybe more.
                  Originally posted by Boogie Bill
                  I've got 60 guitars...but 49 trumpets is just...INSANITY! WTF!

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                  • #39
                    Re: Pictorial of Biasing a Marshall Jubilee.

                    Vaulted

                    Thanks Joe!

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