2203KK KT88 retube options

Discussion in 'The Workbench' started by thunderstruck507, Aug 22, 2019.

  1. thunderstruck507

    thunderstruck507 Well-Known Member

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    Since my 2203KK has the stock KT88 that seem to be dated 2007 I am contemplating switching them for some new ones. The amp has some road wear and indications it could have been a gigging amp before I purchased it and I have had it for a year now with some fairly regular high volume use once per week and practice volume use more often than that.

    I see the EH quads of KT88 for around $140+. There are also offerings from Mullard, Svetlana, JJ, Tung Sol, Psvane...and of course the reissue Genalex Gold Lion.

    I have biased the amp up hotter than stock but not crazy, it's at 68mV per pair now.

    Can anyone honestly say the Gold Lions are worth the extra price over the competitors? I'm not opposed to spending the extra but if it's just flushing $40-60 extra dollars down the toilet then I would rather not.
     
  2. Filipe Soares

    Filipe Soares Well-Known Member

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    I don't know if my opinion will help you in any way, but... here it goes: I own a major with the one cable (RT) mod and I'm using JJs and it sounds KILLER. I've paid something around 140usd for the quad.

    I am saying that because no one have a jcm800kk to play jazz, so I think for high gain the JJs are a solid choice.
     
  3. bigbadorange

    bigbadorange Active Member

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    Just saying hello as a recent addition to the 2203kk owners club. :cheers: Just really starting to get into it. oddly enough I found I prefer a clean boost into it over the "beast" mode. Put an THC hotplate on it and the amp really screams. A very nice addition to the family. Mine looks brand new so it has either seen little use or the previous owner(s) took VERY good care of it.
     
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  4. thunderstruck507

    thunderstruck507 Well-Known Member

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    I sometimes use a Black Arts Toneworks Black Forest Overdrive as a mostly clean boost. The amp is an animal with the Beast mode on but the assault set at 9oclock though...gets really tight and crunchy.

    Don't need the hotplate though, I practice at home with the volume at 2.5-3 and at band practice crank it to 5-6. It roars.
     
  5. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    That 34mV per tube or 68mV a pair is a lower bias. Try them up to 46mV per tube, 92mV per pair or so and find a spot you like most. I will sound better with a high idle bias.

    I remember people liking the 2203KK biased in the 40's per tube.

    Try it on the used tubes and see what they do.
     
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  6. thunderstruck507

    thunderstruck507 Well-Known Member

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    I was going to try that once I get new tubes here. I just am not sure how to know if I'm taxing the output transformer too much when I play with the amp cranked.

    The stock bias was set to 52mV per side. It does sound better at 68 than that. I was just starting out in a known safe zone.

    I measured my voltage at the pin of the power tubes at 448v with power on and standby off.
     
  7. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    448VDC is a good place to be.
    That 52mV/pair or 26mV per tube is way low on a 6550/KT88.
    If it were mine I would be listening and picking something between 35mV to 45mV per tube.
    If you play mostly at lower volumes stick to the higher current idle bias, higher volumes use a lower idle bias current.
     
  8. thunderstruck507

    thunderstruck507 Well-Known Member

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    At home I play at 2.5-3 on master volume usually. Anything quieter and I'll just use my Joyo Zombie.

    At band practice it gets driven to 5-6. We play somewhat doom metal/rock (think Red Fang) with a loud drummer.
     
  9. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    I would be tempted to try the Shuguang as well as EH.
     
  10. thunderstruck507

    thunderstruck507 Well-Known Member

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    I have yet to be impressed with a Chinese made tube (although that is supposedly what the stock KT88s are with a Marshall logo on them).

    In fact the 2 Chinese made 12ax7 I have are the absolute worst I've ever heard. Sterile and lifeless.

    Might just be bad luck...but I don't see myself spending that kind of coin on them to be honest.
     

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