'76 Marshall JMP 2203 with Custom High Gain Mod

Discussion in 'Marshall Amps' started by Eddylenz, Mar 5, 2021.

  1. Eddylenz

    Eddylenz Well-Known Member

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    Hi Everyone,

    I just finished modding this amp with a custom 4 stage non-cf high gain mod. It's based on the gain channel of my 2 channel prototype, but I've tweaked it for a long time. It also has a tube fx loop.

    There's a bass shift switch on the bass pot, a mid voicing switch on the gain pot, and a gain structure switch, that takes away some saturation.

    It can do crunchy 70s, 80s Hard Rock/Metal, and more modern Metal sounds.

    Let me know what you think!

     
  2. Old Punker

    Old Punker Well-Known Member

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    Wow! If you are going straight into the amp then you have created a Metal Monster!
    Sounds great with all of those guitars too. :headbanger:
     
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  3. Eddylenz

    Eddylenz Well-Known Member

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    Thanks!
    It's straight in :D
     
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  4. bigbadorange

    bigbadorange Well-Known Member

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    Freaking awesome, right up my alley! I for sure hear detuned, and/or possibley a 7 string?
     
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  5. Eddylenz

    Eddylenz Well-Known Member

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    Thanks! I used my Charvel in Drop C with 10-52 for the intro
     
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  6. southbound suarez

    southbound suarez Active Member

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    Very interesting!
    I have an old 77 2203 that was Demeter Modded according to the label stuck upon the rear.
    It is stored in back on a pile of future amp projects.
    I just had a newer 2203 across the bench last week and was impressed with how well and how good the tone was for a master volume amp. It had me jonesing on that old 2303 that I have as a project. Now I must go dig it up and see what was done with it... I know that it had been modded into dual foot switchable channels and utilizes dual gang pots with inner and outer shafts . Switching handled by a perf board loaded with several vactrol optical devices.... Hmmm???
    I never was a fan of master volume amps but that last stock 2203 has me intrigued and now this..
    Forgive my ignorance but you mentioned "non CF gain mod" what is CF Gain?
     
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  7. Marshall50w

    Marshall50w Well-Known Member

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    Sounds awesome, all the sounds from great cleanish crunch through to glorious all out. Now I get the 'riding the volume pot' ! not forgetting, proper great playing.
     
  8. Eddylenz

    Eddylenz Well-Known Member

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    Nice! It would be really interesting to hear that one.

    CF is cathode follower. This one has a plate-driven tone stack.
     
  9. solarburnDSL50

    solarburnDSL50 Well-Known Member Platinum Supporting Member

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    I hate reverse headstocks. The rest of the guitar is kill.

    My mutherfucker knows how to tune a vintage Marshall. Sounds really wet without any lube. Sticky when you want.

    Still? I prefer my Metal zone.:eddie:

    That shit does what I'd want a JMP to do. Loved the Lynch! I'll take 2!
     
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  10. Eddylenz

    Eddylenz Well-Known Member

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    Thanks haha!

    I love reverse headstocks and hate Metal Zones ;D
     
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  11. solarburnDSL50

    solarburnDSL50 Well-Known Member Platinum Supporting Member

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    :lol:

    That amp sounded so good. Killer!:flex::drool:
     
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  12. dslman

    dslman Well-Known Member

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    Sounds great!! Very aggressive also.
    Do you mind me asking what bright cap value, you have on the amp?
    Thank you.
     
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  13. Eddylenz

    Eddylenz Well-Known Member

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    Thanks!
    There's no bright cap on the gain pot. I always try to design my circuits without one, so you can really use the gain control as a gain and not a fatness control.
     
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  14. dslman

    dslman Well-Known Member

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    Wow, that’s pretty impressive then. Great work!
     
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  15. Eddylenz

    Eddylenz Well-Known Member

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    Thank you!
     

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