Mod Gone Wrong?

Discussion in 'The Workbench' started by Neddi, Jun 16, 2019.

  1. Neddi

    Neddi Member

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    hello all - I recently had a 1978 JMP 50 watt modded by a guy and here is the situation - when I sent him the amp it had a fully functional Metro loop - when I got the amp back the loop was not working properly - It's almost as if the loop was sitting somewhere in the preamp section because when I plugged the guitar into the return of the loop it sounded dirty as if I was plugged into the front of the amp - I contacted the person that did the mod and he told me it had to be the loop that had gone bad and I should have a new loop installed - I did just that and it's the same problem - I'm here talking to you guys because I want to get this amp working properly and I don't know where to go with it - I'm in Milwaukee and I'd like to send it to someone who can get it working proper - thanks, neddi
     

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    Last edited: Jun 18, 2019
  2. ampmadscientist

    ampmadscientist Well-Known Member

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    Start the reactor... Free Mars!
    The return of the effects loop should be clean. It should not be distorted...

    Maybe if you post a lot of good clear close up pictures we could look at it...
    but you will probably need to do it over.

    If you need a tech to fix up modify the amp, I would recommend http://www.marshallforum.com/members/newreligion.9403/
     
    jstich and neikeel like this.
  3. ampmadscientist

    ampmadscientist Well-Known Member

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    Start the reactor... Free Mars!
    Welcome to the forum Neddi :cheers:.
    Congratulations on that first post.
     
  4. 67Mopar

    67Mopar Well-Known Member

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    Last edited: Jun 16, 2019
  5. pedecamp

    pedecamp Well-Known Member

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    I was like uh-oh, what did @Dogs of Doom do wrong this time...:ugh:

    :rofl:
     
  6. Nik Henville

    Nik Henville Well-Known Member

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    Damn...

    You beat me to it by four minutes!

    :hippie::uk:
     
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  7. MarshallDog

    MarshallDog Well-Known Member Premium Member

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    Welcome to the Forum and good luck getting that amp fixed!!!!
     
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  8. Nik Henville

    Nik Henville Well-Known Member

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    Dogs of Doom and crossroadsnyc like this.
  9. tce63

    tce63 Well-Known Member Premium Member

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    :welcome: to the forum, good luck with the amp
     
  10. pedecamp

    pedecamp Well-Known Member

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  11. crossroadsnyc

    crossroadsnyc Senior Moderator Staff Member

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    The penitentiary, no, but the insane asylum ... um, arguable!
     
  12. fifteenohms

    fifteenohms Well-Known Member

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    Wow sorry to hear another sad mod story.

    I used to be excited to give out modification referrals because when done right that’s what it is: exciting.

    Mods I’ve had done are setup properly with low noise and good hardware practice. I am not afraid of leaving home with them, they were done well and I encourage you to keep trying.

    They guys I used to refer for this type stuff are all now famous amp builders in their own right: now I don’t know who can be trusted anymore.

    Someone here is sure to be helpful.
     
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  13. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    :welcome: Neddi

    Along with the pictures requested can you tell us about or describe the modification(s), what it does and it's whereabouts inside the amplifier?
     
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  14. Dogs of Doom

    Dogs of Doom Moderator Staff Member

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    I live not too far from here! :)...

    [​IMG]
     
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  15. Neddi

    Neddi Member

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    how can i message you? i'm not too tech savvy
     
    Last edited: Jun 17, 2019
    tce63 likes this.
  16. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    conversation started
     
  17. Neddi

    Neddi Member

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    the amp has the R/T mod done by Michael R/T - he's offered to help with this situation so if anyone wants to help he's available to answer questions - i know nothing about the internals
     
  18. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    Well that is a good thing. :yesway::)

    Are we going to get descriptions, pictures and maybe even diagrams?
     
  19. charveldan

    charveldan Well-Known Member

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    Impossible to diagnose over the internet without all parties involved and even then very difficult.
     
  20. fifteenohms

    fifteenohms Well-Known Member

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    All 12ax7’s are functioning?

    If the mod is tube-driven the hang may be a bad tube since the guy says it shipped okay
     

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