Who Can Build A Mini Major?

Discussion in 'Building the Classics' started by JKrauland, Jun 14, 2018.

  1. JKrauland

    JKrauland New Member

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    Who's a solid builder I could commission a Mini Major from? I did some research and saw that fusionbear and danfrank have done builds. My main goal is to preserve the original circuit while lowering the power needs and weight of the amp. So at most 100W but ideally even lower. If it could fit into a jtm45 size head cab that would be great. As long as its under 40 pounds i'm a happy camper.

    Thanks a bunch
     
  2. Coronado

    Coronado Well-Known Member

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    If I'm not mistaken, didn't Micheal RT just build a multi-watt Major? I could totally be wrong here, my apologies if I'm remembering this incorrectly.
     
  3. AlvisX

    AlvisX Well-Known Member

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    Just being curious. What is the appeal of a mini Major ?
    Is the purpose to achieve a loud,clean signal, or how would it differ from what you could do with a plain ol' 100 watter
     
  4. m1989jmp

    m1989jmp Active Member

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    Quite a few differences when compared to, let's say, Marshall 1959. Notably cathodyne PI and output transformer with ultralinear taps.
     
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  5. ampmadscientist

    ampmadscientist Well-Known Member

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    About 40 watts is enough to blow out of the room. 100 would be absurd.
     
  6. Guitar-Rocker

    Guitar-Rocker Well-Known Member

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    For once, I agree with MAS. Well put.
     
  7. AlvisX

    AlvisX Well-Known Member

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    Yes, the schematic differences are understood ,having spent a good bit of time inside the Major. My opinion of the Major is that it's a LOUD/ clean amp...pretty well up the dial.That's one of the reasons I got one,to play bass out of it .
    Other than that ,I was tryin' to understand what tonal characteristics one might be lookin for out of a Major ,or a mini Major

    Now as I said, I find it to be a loud clean amp up the dial,especially with guitar.....crispy.
    Not a sustain-y amp,so to speak.It really feels like you gotta you gotta have some kind of trick to get a little grind n juice out of it .......
    Blackmore's alleged tape recorders /reverb units /cascade mods
    R/T's outa sight one wire ,My 2203 mod ....somethin
     
  8. BowerR64

    BowerR64 Well-Known Member

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    Well yeah he would want the same exact preamp as the major but then redo the power section so that it is anything but 200 watts.

    Then do the same mods as R/T or the one wire mod or what ever to get the same sort of grit.

    I wouldnt mind one of those myself, everything exactly the same as the major with the same R/T type of mods but without the PIG power.

    The problem is the budget
     
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  9. printer

    printer Member

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    So just a jtm45 preamp and a clean power amp until the output clips, say 40-50W?
     
  10. BowerR64

    BowerR64 Well-Known Member

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    Your saying a JTM45 is the same as a major? I thought the major with all the holes is a diferent thing?
     
  11. J5684

    J5684 Member

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    There are a few different "Majors" the PA is the one with all the inputs. There are two version from what I remember. The first version had the split tone controls "ala" Sound City amps design. The 2nd version went back to the standard passive tone controls.
     
  12. printer

    printer Member

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    I just took a look for other schematics, I see this one does not have different cathode biasing but is more in line with the Bassman. But that makes sense if it was to be used for a PA amp.

    [​IMG]

    As compared to this,

    [​IMG]

    or,

    [​IMG]

    No idea if there are more out there.
     
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  13. AlvisX

    AlvisX Well-Known Member

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    Mine is a '68 PA,that I snatched out of a guitard center of all places
    It had an absolutely horrible squeally one wire mod on the 1st two channels , which guitar center guy described as "some distortion"
    Force of habit , I changed it to basically a 2203 preamp
    The other 2 channels are left alone 'cept for a brite cap on one
     
  14. ampmadscientist

    ampmadscientist Well-Known Member

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    Pretty much "any": Plexi kit can be easily changed to a mini major.....so there is really no need to start from scratch.
    Pretty much any Plexi / 2204 which is already built can be easily changed.

    POWER
    Changing output tubes to Triode will give you 40W from a 100W amp. OR
    alternative is to use a multi-tap power transformer (such as classic tone) to lower the B+ voltages.
    It is really easy to change the output to triode.

    I build / change Triode amps all the time, and it's a good alternative to over-powered amps.
    I find 18W to be plenty....
    50 watt amp changed to triode is about 18 watts.
    The thing will blow you away at 18 watts, it's loud past ridiculous.


    But really: I don't see any advantage. (unless you play bass?)
    The Major is going to have a clean preamp and it will be cranked up to get output tube distortion....just like a Plexi.
    Not a whole lot of difference tone-wise, between Major and Plexi. They are almost the same anyway....except for the brightness of Plexi which is a small difference in parts.
     
    Last edited: Jun 18, 2018
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  15. mAx___

    mAx___ Active Member

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    Mini Majors have become very popular lately. I can only say good things about mine now that I have redone it to "Blackmore" specs. By itself the Major is useless for lead guitar tones. But once modded it becomes IMO one of the best sounding plexis there are. There is a very noticeable difference in sound between a Major and a Lead or Superlead amps. I'm sure it also applies to Bass spec plexis. Very different circuit and components.

    Be careful with those schematics posted above as they have multiple errors. The .47uF caps after the driver stage should be .047uF and the 250R screen grid resistors should be at least 10W. Original spec is 250R/25W. There's probably more.
     
    Last edited: Jun 19, 2018
  16. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    Why not just call it what it will be, a Mini or whatever? Drop the Major because once modified out of power category it is no longer a Major.
     
  17. mAx___

    mAx___ Active Member

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    It's still a Major circuit. If you don't call it a (mini-, half-, etc.-) Major, nobody would have any idea of what amp you're talking about. That said, one builder in Germany calls his " the Minor".
     
  18. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    I would rather it be called the Minor.

    All Major amplifiers are 200 watt, supposedly.

    I am still considering them modified Bassman amplifiers anyway.
     
  19. mAx___

    mAx___ Active Member

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    The OP asked for a "Mini Major" build, implying a less-than 200W amp. I prefer to describe mine as a "2xKT88 Major build" so that people reading posts or watching YouTube understand that it's a half-powered version of the original. That way I can also appear in YT searches for "Marshall Major". By now it seems that mostly everybody calls it Mini Major though. I don't think you can remove the Major from the name without losing track of what it is. Like just calling "the Mouse"to Mickey. Which mouse? :D
     
  20. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    So that would be a Half Major.

    I am just pulling yous guys strings. Call it what you want. :D
     
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