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  • Blue Kt77 Power Tube

    My amps take EL34, 6CA7, KT77 or KT88 power tubes. The preferred tube by many for my amps are the KT77. I have been using KT88 and EL34. My KT88 wore out so I decided to get some KT77 Gold Lion. I bought them from Antique Electron Supply. I figured with their Apex machine they should be matched well. I install the first set and they seem to work fine. All glow orange. I put the second set in and fire it up. One tube starts to turn iridescent blue inside the plates so I shut it down. Wait a while and try it again. Again it turns blue. I wasn't seeing things. I send them back to Antique Electron Supply and I am told they all check out fine. No explanation on why at least one runs blue. I asked they check again but I'm feeling like I got some crap tubes and there mine now.

    Anyone want to buy some tubes that are suppose to be fine but 1 maybe 2 turn blue in about 10 seconds into powering up. I don't know for sure as I did not spend a lot of time observing. This is initial startup of a new tube. My amps don't have any built in protection so I sit there with any new tubes, finger on the power switch ready to flip it off. I have experienced a catastrophic tube failure in the past. It's scary as all get up. Super loud bangs from the speaker. Archs flashing in the tube. It's kind of unnerving reaching towards the amp to flip the power switch. Yes the fuse is suppose to blow but it can take some time to get there. I have never had any other tube go blue in my amps. I have used maybe 5 differ types/brands of tubes in these amps. I currently have some JJ EL34 running now. They all hold excellent bios and burn a pretty orange.

    Do I tell them to throw the tubes out and buy somewhere else or is there a more reliable place to have them tested to ensure I don't damage my equipment. I cant really take them by my local shop. The owner kind of rubs me wrong. He want to sell tubes too. His claim to greatness is he gets his tubes tested by New Sensor. Big Whoop. Everyone says they get their tubes tested there and only get the cream of the crop. Someone is getting the bottom 50%. Even the bottom 20%. I thought Antiques Apex machine would get me good tubes. I really don't know where to buy tubes from now.

    Oddly, I had a set of Gold Lion KT77 I got from Upscale. I used them for about 3 months in my Altec as drivers. Something went unstable so I pulled them an went back to NOS JAN Phillips 6CA7. I took the KT77 I had to the local shop I don't like so much and all 4 tested with Shorts. 3 about 400 and 1 that was around 1100. Maybe I wrecked those tubes. The rebuilder of my amp after I told him the experience said don't use Kt77 as drivers for some reason I don't remember. Anyhow, I almost wonder if the Gold Lion KT77 is not a very reliably built tube??????????? It is very possible I just ruined the 4 from Upscale. I don't really know. But in my mind. I have now had 5 out of 8 of these tubes fail.
    PAP Trio 15 Horn speakers, Audion Black Shadow monoblocks, First Sound Audio Mark 3SI Paramount preamp,
    Mojo Audio Deja Vu server, Mojo Audio Mystique V3 DAC, STST Motus II TT, Vertere SG1 arm, Hanna ML, Allnic H1201 Phono pre, The Linear Solution Ethernet Switch, LPS to Modem Router and Switch, Blue Jeans Ethernet cabling throughout network, Akiko Corelli, Custom power strip direct wired to panel with OFC copper wire.10 awg dedicated branch circuits to amps bolted to power cords. Significant upgrades to 120 volt main power panel. Inakustik Ref Air 2404 Speaker cable. Genesis and Inakustik NF2404 Air Interconnects. ADDPower Symphony and Electraclear.

  • #2
    So they wrote back and said they could do a return and credited me my money. I wasn't really asking for that. I want a quad of tubes. I just want ones that wont detonate or pre fail and possibly damage my amp.

    According to Antique Electron:
    We didn't see any blue, but upon further research, power tubes that glow blue aren't an issue. Blue inside the tube is a sign of it having good vacuum, as opposed to a purple cloud which would be a sign of a defect. It's not common for them to glow blue, but it isn't a defect.

    Maybe this is true. I really don't know. I never heard as such. Anyhow, I feel a little frustrated. I kind of felt I had a quality New Sensor supply house. I just don't know what is true and not.
    PAP Trio 15 Horn speakers, Audion Black Shadow monoblocks, First Sound Audio Mark 3SI Paramount preamp,
    Mojo Audio Deja Vu server, Mojo Audio Mystique V3 DAC, STST Motus II TT, Vertere SG1 arm, Hanna ML, Allnic H1201 Phono pre, The Linear Solution Ethernet Switch, LPS to Modem Router and Switch, Blue Jeans Ethernet cabling throughout network, Akiko Corelli, Custom power strip direct wired to panel with OFC copper wire.10 awg dedicated branch circuits to amps bolted to power cords. Significant upgrades to 120 volt main power panel. Inakustik Ref Air 2404 Speaker cable. Genesis and Inakustik NF2404 Air Interconnects. ADDPower Symphony and Electraclear.

    Comment


    • #3
      Hahahaha the blue does not mean a good vacuum atleast I can’t see how. But the blue means a higher plate usage. Power tubes show this due to high current. Do the plates turn red ? This means plate saturated and over biased or driven. I’m no tube expert but this seems Basic. I do know there are tubes made that do glow colors due to some gas inside them. I remember as a kid looking at a grundig amp glowing looked cool.
      mad for the tubes you choose. Each type has its sound and power level lot sound best.
      i think over all check biasing and heater vol / current
      analog stuff.
      otari mtr 10 2 track 1/4 made new by soren
      otari mtr 10 2 track 1/4 1/2 combo made new by soren
      sota sapphire used eminent tech ver 2 arm
      new sota nova table has magnetic levitation platter and full speed control and latest motor same arm as above
      thorens td124 sme ver 2 arm
      thorens td125 sme ver 2 arm
      kenwood direct drive sme ver 2 arm
      phono preamp Ml no 25 all re capped
      speakers cust infinity IRS V , new caps and LPS , magnets etc.
      mark levivson pre no 26 amps no 33
      digital three cust servers , win ser 2016 , AO
      Dacs lampi various

      Comment


      • #4
        Your tubes are fine , blue glow is not a defect. It is common in new production tubes. The electrons are hitting the glass.

        You can google some tube vendor sites and this is explained the same way in many places.
        Front end: Aesthetix Io Eclipse with 2 Power Supplies and Volume controls
        Brinkmann La Grange & RonT Tube Power supply with Kuzma 4-point ,FR64S, Brinkmann 12.1 , .Koetsu Jade Platinum,Koetsu Rosewood Signature Platinum, Lyra Atlas, Lyra Etna SL Goldfinger Statement, KLAUDIO RCM, HRSM3X
        Amps: Wyetech Topaz, Futterman H3 Quad II,Citation II, Marantz 8b, 5 ,2
        Pre-Amps:Marantz 7, Marantz Model 1 Consolette Pair
        Speakers: Quad ESL 57, Beveridge Model 3 DD amps, REL S/2 x 2
        Otari 5050BXII, DeHavilland 222

        Comment


        • Kingrex
          Kingrex commented
          Editing a comment
          I will look. I always thought it was overbios, but my bios was set to minimum and pushing .030 mili volt. When set properly it should be .450. I was way under.

          I am cautious as I said above. I don't have failure protect like VAC amps. They could add it but they say it affects sonics.

          Still seems weird to me. I have never seen it. Only in video of overbiosed tubes.

        • Kingrex
          Kingrex commented
          Editing a comment
          Ok, I looked around and found a tube sites that sell New Sensor tubes saying it's not unknown and generally has no affect on sound. I did not see any good reason for it. It says electrons are bouncing off the glass. But why are they doing it on only a few tubes and not all tubes. I would prefer tubes that look and act normal all around.

          Atmasphere, what do you think? You build tube amps. You ok with a tube glowing blue. Would you send an amp out the door with a blue tube???

      • #5
        Rex play and enjoy there are so many intriguing things in audio. I do feel the glow of tubes is like salt lamps it just adds calm to the effect of sound. As for electrons bouncing I’ll bet it’s true in gate leakage
        you can effect the sound of tubes in many ways. Even pulsing brite lights, magnets and even acoustic noises. Did it sound better or altering when you fixed the bias ?
        analog stuff.
        otari mtr 10 2 track 1/4 made new by soren
        otari mtr 10 2 track 1/4 1/2 combo made new by soren
        sota sapphire used eminent tech ver 2 arm
        new sota nova table has magnetic levitation platter and full speed control and latest motor same arm as above
        thorens td124 sme ver 2 arm
        thorens td125 sme ver 2 arm
        kenwood direct drive sme ver 2 arm
        phono preamp Ml no 25 all re capped
        speakers cust infinity IRS V , new caps and LPS , magnets etc.
        mark levivson pre no 26 amps no 33
        digital three cust servers , win ser 2016 , AO
        Dacs lampi various

        Comment


        • Kingrex
          Kingrex commented
          Editing a comment
          As soon as I saw blue I shut them down and sent them back. I never got to turning up the bios the hear them. They only ran for 10 or 15 seconds. No volume was present.

      • #6
        Damn ok.
        analog stuff.
        otari mtr 10 2 track 1/4 made new by soren
        otari mtr 10 2 track 1/4 1/2 combo made new by soren
        sota sapphire used eminent tech ver 2 arm
        new sota nova table has magnetic levitation platter and full speed control and latest motor same arm as above
        thorens td124 sme ver 2 arm
        thorens td125 sme ver 2 arm
        kenwood direct drive sme ver 2 arm
        phono preamp Ml no 25 all re capped
        speakers cust infinity IRS V , new caps and LPS , magnets etc.
        mark levivson pre no 26 amps no 33
        digital three cust servers , win ser 2016 , AO
        Dacs lampi various

        Comment


        • #7
          I'm going to order more. Not sure if I want to use the same place. I may just get the ones I ordered before back again. Haaaaa. But who else sells New Sensor power tubes and really test them proper. And what is proper. My local guys bags on everyone (very annoying). Anyhow he says no one test under load to understand what the tube is really doing. I just don't get how a real tube seller would not have a piece of equipment that did as such.
          PAP Trio 15 Horn speakers, Audion Black Shadow monoblocks, First Sound Audio Mark 3SI Paramount preamp,
          Mojo Audio Deja Vu server, Mojo Audio Mystique V3 DAC, STST Motus II TT, Vertere SG1 arm, Hanna ML, Allnic H1201 Phono pre, The Linear Solution Ethernet Switch, LPS to Modem Router and Switch, Blue Jeans Ethernet cabling throughout network, Akiko Corelli, Custom power strip direct wired to panel with OFC copper wire.10 awg dedicated branch circuits to amps bolted to power cords. Significant upgrades to 120 volt main power panel. Inakustik Ref Air 2404 Speaker cable. Genesis and Inakustik NF2404 Air Interconnects. ADDPower Symphony and Electraclear.

          Comment


          • #8
            Lol. I think most tube sellers don’t care to complex to try. I buy new when I can not used nos again it’s still Tested as new.
            if I were you would contact George Lenz
            he is a tube dealer here long isld
            great guy all know him here. He has a few tube testers one is the ampex 3k
            he has been to my place to test tubes in my head phone amps too.
            analog stuff.
            otari mtr 10 2 track 1/4 made new by soren
            otari mtr 10 2 track 1/4 1/2 combo made new by soren
            sota sapphire used eminent tech ver 2 arm
            new sota nova table has magnetic levitation platter and full speed control and latest motor same arm as above
            thorens td124 sme ver 2 arm
            thorens td125 sme ver 2 arm
            kenwood direct drive sme ver 2 arm
            phono preamp Ml no 25 all re capped
            speakers cust infinity IRS V , new caps and LPS , magnets etc.
            mark levivson pre no 26 amps no 33
            digital three cust servers , win ser 2016 , AO
            Dacs lampi various

            Comment


            • #9
              I ordered another set from Antique Electron. Ampsandsound get there tubes from there. I added in the notes a request I do not get the same quad back again. And to please ensuer non burn blue. We shall see.
              PAP Trio 15 Horn speakers, Audion Black Shadow monoblocks, First Sound Audio Mark 3SI Paramount preamp,
              Mojo Audio Deja Vu server, Mojo Audio Mystique V3 DAC, STST Motus II TT, Vertere SG1 arm, Hanna ML, Allnic H1201 Phono pre, The Linear Solution Ethernet Switch, LPS to Modem Router and Switch, Blue Jeans Ethernet cabling throughout network, Akiko Corelli, Custom power strip direct wired to panel with OFC copper wire.10 awg dedicated branch circuits to amps bolted to power cords. Significant upgrades to 120 volt main power panel. Inakustik Ref Air 2404 Speaker cable. Genesis and Inakustik NF2404 Air Interconnects. ADDPower Symphony and Electraclear.

              Comment


              • #10
                Originally posted by Kingrex View Post
                According to Antique Electron:
                We didn't see any blue, but upon further research, power tubes that glow blue aren't an issue. Blue inside the tube is a sign of it having good vacuum, as opposed to a purple cloud which would be a sign of a defect. It's not common for them to glow blue, but it isn't a defect.

                Maybe this is true. I really don't know. I never heard as such. Anyhow, I feel a little frustrated. I kind of felt I had a quality New Sensor supply house. I just don't know what is true and not.
                This is called fluorescence. Since no tube has a perfect vacuum, a few air molecules are still in the envelope. When there are high voltages present and enough current, the molecules can glow in a bluish light; similar to what causes aurora borealis. Its rare to encounter a power tube that does not do this but some have to be viewed in darkness to see it. The fluorescence can flash to the beat of the music- the harder the tube has to work the more it will fluoresce. In the old days it took more to get tubes to do this, and no mistake it does cause the tube to run a little hotter. But a perfect vacuum is pretty hard to accomplish so you're always going to see some. I don't regard it as a defect; its a sign that the tube is working.

                Comment

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