Early JMP 50 watt just finished

Discussion in 'Building the Classics' started by william vogel, Mar 25, 2020.

  1. william vogel

    william vogel Member

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    466A0A7E-54B5-4DFC-8CCA-ED70C88548E6.jpeg 7D494E41-FED9-4726-B8AD-E469AA9680DB.jpeg AFAF5B04-2932-4B53-AA4C-BF39531E9FD4.jpeg 6DA495A0-E260-4B09-9070-F659E45BFF48.jpeg C21251A9-80A4-4DCB-8BA0-5A1EB166192B.jpeg I just finished this one up 2 weeks ago. It really does everything well. Switches let me choose lots of voices. Late 67-early 70’s.
     
  2. GIBSON67

    GIBSON67 Well-Known Member

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    Good job, I really like where you put the switches.
     
  3. pedecamp

    pedecamp Well-Known Member

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  4. neikeel

    neikeel Well-Known Member

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    Nice build with some neat extra features. I like the power supply board for the diodes and heater centre tap arrangement.
    What were your filtering choices?
    I presume you do not switch tone stack etc very often.
     
  5. South Park

    South Park Well-Known Member

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    Nice build any gain mods
     
  6. StingRay85

    StingRay85 Active Member

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    Looks awesome
     
  7. harleytech

    harleytech Well-Known Member

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    very nice !
     
  8. Kelia

    Kelia Well-Known Member

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    `Nice build ,..........Clip would be great ! :thumb:
     
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  9. william vogel

    william vogel Member

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    Filtering switches from 50uF to 100uF. I actually swap around a bit. I really prefer input 2 top set like a JTM50.
     
  10. HOT TUBES 70

    HOT TUBES 70 Well-Known Member

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    Pro quality work right there ... Looks fantastic.
     
  11. Exojam

    Exojam Well-Known Member

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    Looks very nice.

    Just wondering how you access the switches?
     
  12. Bruce_W

    Bruce_W New Member

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    That is a beautiful amp. Real nice job. Would you mind posting the voltages from the preamp tubes ? Pins 1, 3, 6, and 8? Just so I can compare to mine I just finished. It sounds decent but seems to be a little low volume and a little too clean.
     
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  13. ampmadscientist

    ampmadscientist Well-Known Member

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  14. william vogel

    william vogel Member

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    If you go to Valvestorm and use the build checklist, you’ll see how it can be ordered. I build amps often and have many of the small parts on hand, resistors, caps, pots, etc. I buy the chassis and sometimes the board, they have really nice stuff and it works great and sounds REAL. Give them a try. Oh, I just finished a jtm45 this morning and I’ll post pictures later. I build my own cabinets.
     
  15. william vogel

    william vogel Member

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    I’ll have to open it back up later but I’ll do it and post voltage.
     
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  16. william vogel

    william vogel Member

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    It’s really easy for me because I don’t run the amp with the rear panel installed, let’s the heat dissipate better. All you do is reach over the preamp tubes for the tone switches and the filter switch is between the power tube and the cap can. Really easy.
     
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  17. _Steve

    _Steve New Member

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    Great work!

    How do the two filter settings sound?
     
  18. william vogel

    william vogel Member

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    The lower filtering is a little bouncier and the heavy filtering works good for tightening the amp up but it’s not a night and day difference. It’s far from jtm45 vs late JMP. It’s just a nice added bonus to the preamp switches.
     
  19. _Steve

    _Steve New Member

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    Cool thank you! Im gonna add this switch to my current build to hear how it sounds. I've never thought about making any of the filter caps bypassable.
     

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