Jolida JD-502P and the Tung Sol KT-150

Discussion in 'Jolida Audio' started by jedinite24, Nov 4, 2014.

  1. jedinite24

    jedinite24 Member

    Just putting this out there as an FYI.

    One can put a quad of Tung Sol KT-150s in the Jolida 502 series amp or integrated without it blowing up. Be sure to lower the bias before putting in these tubes. Also if you have the tube cage it won't fit over the amp because of the height of the KT-150s. That may be a good thing due to the amount of heat your Jolida will put out with the KT-150s in place.

    As for SQ I like the 502P even more with the KT-150s in place. They replaced a set of Blue Glass JJ KT88s which had a little bit of a boomy bass in my system. With the KT-150s in place the bass was tighter and the highs were more open to me in my system.

    Jolida 502P KT150_photo 1c.JPG
  2. Lewis Smith

    Lewis Smith Well-Known Member

    What did you Bias them at??? compared to the KT88's
  3. jedinite24

    jedinite24 Member

    Hi Lewis

    I make sure I bias the Tung Sol KT-150s at about 55o millivolts. The problem though is that the tubes are so big and wide that I often singed part of my hand due to my radioshack meter having such small leads. For the JJ KT88s and other 6550 tubes I biased them around 530 to 560 Millivolts. The reason why I did that was because the voltage in my house isn't stable and whenever I saw the red lights twinkle it would bother me. When I borrowed a set of Tung Sol KT-120 tubes it took forever for the red lights on the Jolida to light up.
  4. A. Smith

    A. Smith Well-Known Member

    Didn't know they were up to that model # now. The last time I rolled power tubes was KT-90's in my old Mesa Baron.
  5. jedinite24

    jedinite24 Member

    Hi A Smith

    I think you will get a kick out of this pic. The tubes just keep getting larger & larger. the odd tube out on the far right is a Russian 6C33C tube. I had all these tubes in my possession at one time and couldn't resist taking a pic. I wish I had a 300B as well as a EL84 power tube in this line-up as well to show the crazy size differences. Power tube size comp.JPG
  6. A. Smith

    A. Smith Well-Known Member

    Yeah, I've seen 300B's and 2A3's, etc. But I've been out of the tube thang for several years now.

    Those all look like they've been eating 'Merkin fast food.

    "New Study: 68.5% Of Power Tubes Are Overweight Or Obese"

    "Research also shows that the heaviest tubes have become even heavier the past decade"


    ;)
  7. Lewis Smith

    Lewis Smith Well-Known Member

    What are those tube dampers on the tubes i haven't seen those before and do they work?
  8. jedinite24

    jedinite24 Member

    Hi Lewis. Sorry for the uber late reply. I never got an e-mail saying there was an update to this thread. Those tube dampers are from Herbie's Audio Lab.

    http://herbiesaudiolab.net/preamp.htm

    They are to help with microphony. I have my Jolida near my speakers so any kind of damping will help.

    I went with Herbies because I just got tired of the orange o rings I've seen in the past.
    Lewis Smith likes this.

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