Clone Kits For Jtm50

Discussion in 'Building the Classics' started by 6string, Feb 20, 2018.

  1. Kelia

    Kelia Well-Known Member

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    If I’d be looking for a JTM50 which I’ll be soon , the only tranny’s that would go in
    for the 3D warm overtones are the Marstrans !
     
  2. Mike.Welch

    Mike.Welch New Member

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    ampmadscientist said:
    it is not legal to use the aluminum chassis as a current path​

    What does it mean to use the chassis as the current path? I only use the chassis to attach my preamp ground on one end of the amp and attach the power amp ground on the other end. I have never hear of the "signal" going through the chassis. Can you give an example?

    Mike
     
  3. danfrank

    danfrank Well-Known Member

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    Old marshall amps where wired this way... Pin 8 of the power tubes were attached to the chassis as a return path; so in essence, the chassis in these amps were a current path for the amp.

    IMG_7093.jpg

    This is bad design as it makes for a noisy amp.

    You should also attach power supply and audio ground to chassis at only one point in the amp... I usually use the negative (-) end of the main (1st) filter cap and attach this point to chassis ground, only. This is to eliminate any potential ground loops.
     
    Last edited: Mar 11, 2018
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  4. Mike.Welch

    Mike.Welch New Member

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    Thanks danfrank. That makes sense. I've never done that, but I have seen some builds like that.
     
  5. S.Marshall

    S.Marshall New Member

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    Built this JTM 50 awhile back with Marstran iron. Hand made a custom polished SS chassis. Amp sounds amazing. PC152497 - Copy.JPG JTM50-7 - Copy.JPG
     
    coldengray, Metroman, v846 and 2 others like this.
  6. S.Marshall

    S.Marshall New Member

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    Don't let anyone tell you what you can't do. Here's another JTM 50.... kinda. Kits are ok but it's more fun to build what you want. This was a fun one. DSC_0786 - Copy.JPG DSC_0794 - Copy.JPG
     
    Guitar-Rocker, v846, neikeel and 2 others like this.
  7. TAZIN

    TAZIN Active Member

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    Nice work Steve.
     
    BowerR64 likes this.
  8. BowerR64

    BowerR64 Well-Known Member

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    I like where the rectifier is mounted
     
  9. v846

    v846 Member

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    Steve,


    Wow very nice builds, did you use the 784-139 or the 784-128 output ?
    Love those grey RS cap thingies.


    David
     
  10. S.Marshall

    S.Marshall New Member

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    Thank you sir!
     
  11. S.Marshall

    S.Marshall New Member

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    Thanks! I used the 139. One amp has Marstran the other Merren.
    The RS caps are my clones.
     
  12. v846

    v846 Member

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    Nice cap clones :), amps are beautifully done.



    I have a 784-128 in mine using a very early version as example , will post some pics soon..
    Nice cap clones :), amps are beautifully done.


    I have a 784-128 in mine using a very early version as example , will post some pics soon..
     

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