JTM45. Please help me figure out the year….

Discussion in 'Let's Talk Vintage' started by hotrodtikigod, Nov 30, 2021.

  1. hotrodtikigod

    hotrodtikigod Member

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    I was given this amp about 12 years ago. It had a blown PT when I got it. The tech I took it to suggested the MM power transformer. I’ve since learned there are better replacements. It’s been my number one gigging amp for more than 10 years. I could never figure out the year tho. I wonder if it is supposed to have a tube rectifier? I know it looks like it’s been messed with a bit. Everyone was so helpful with my SuperLead, Can someone tell me what I have here?
     

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  2. fitz288

    fitz288 Well-Known Yinzer Gold Supporting Member

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    Close up pic of the serial # might have the info you want.
     
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  3. hotrodtikigod

    hotrodtikigod Member

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    Here is the serial..
     

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  4. tomsvintage

    tomsvintage Well-Known Member

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    Not an expert but I would guess around 66 ish ~ chassis has the block ends that were common during that year :) Not too sure about the circuit
     
    Last edited: Dec 2, 2021
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  5. South Park

    South Park Well-Known Member

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    That silver can at the end is the rectifier . It is not a tube I Sean this on old hifi stuff . It looks like it had a tube rectifier at one time . If the wiring is still thar you can put both of them back . Nice amp
     
  6. Dogs of Doom

    Dogs of Doom >>> Moderator <<< Staff Member

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    can you post a better pic of this?

    upload_2021-11-30_17-6-22.png
     
  7. hotrodtikigod

    hotrodtikigod Member

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    Here you go…
     

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  8. Dblgun

    Dblgun Well-Known Member

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    Looks like a 67 tremolo with a lot going on
     
    Last edited: Nov 30, 2021
  9. Humbucking

    Humbucking New Member

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  10. neikeel

    neikeel Well-Known Member

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    Yes, probably very early 67 as that OT was introduced in Feb 67 and only used in short run. Normally these were JTM50 with EL34s but I think that they used up the MKIV front panels up (same way my similar era 45/100 had EL34s and block end chassis)
     
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  11. hotrodtikigod

    hotrodtikigod Member

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    Ahh, so this is a 50 watt amp. Not 30. That explains a lot, thank you.
     
  12. hotrodtikigod

    hotrodtikigod Member

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    So, is it proper to call this amp a JTM50? or a JTM45?
     
  13. neikeel

    neikeel Well-Known Member

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    It is a JTM50T with a JTM45 faceplate from the factory so I guess it is up to you what you call it, probably transition JTM45 Trem?
     
  14. Ricky Toney

    Ricky Toney New Member

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    Looks like an octal socket second from the corner with diodes. The rectifier tube have been bypass with solid state rectification. You can put a switch and wire to use tube rect or solid state.
     
  15. dro

    dro Well-Known Member

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    Yes it came with tube rectifier. GZ34

    Likely came with KT66 power tubes
     
  16. DeafLeopard1996

    DeafLeopard1996 New Member

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    Wow, what a lovely amp! That's an interesting quandary regarding the tube rectification. Doesn't look like kt66s anymore, was it possibly modded to behave more like a black flag?
     
  17. AndyD

    AndyD Well-Known Member

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    What a gift!!! Worth putting a Marstran transformer in it. Great project if you want it to be. Love the colour of the plexi panels.
     
  18. Luvverly Joobly

    Luvverly Joobly Active Member

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  19. hotrodtikigod

    hotrodtikigod Member

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    Given to me by the best singer I have ever payed with. He picked it up in the early 70’s, but switched to lead vocal exclusively by the mid 70’s. I’ve played in a band with him for nearly 15 years. Oh…. And he was also my father in law for a time. Long story—brief marriage.
     
  20. hotrodtikigod

    hotrodtikigod Member

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    I do have the original PT for it somewhere. I thought about getting it rewound, but I have other amps that need attention and are more of a priority as this amp sounds just fine with the replacement power transformer.
     
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