Who Can Build A Mini Major?

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

  1. danfrank

    danfrank Well-Known Member

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    Mickey takes a back seat to Jerry, in my book.

    BTW, the OP hasn't even replied back to this thread so maybe he's looking for a Blackmore style amp or maybe the other kind...

    I always question when an OP starts a thread and then isn't heard from again in the thread that they started.
     
  2. printer

    printer Member

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    The only thing I see which really sets the amp apart from other Marshalls is the Cathodyne phase splitter and the gain stage after it.
     
  3. danfrank

    danfrank Well-Known Member

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    The Ultra-Linear output stage will also make it sound different than most other guitar amps.
     
  4. ampmadscientist

    ampmadscientist Well-Known Member

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    There is a certain Major which has 6 output tubes. This is a more powerful version (the design is un-stable). This model was discontinued rapidly.
    I have seen 2 of these Majors. I think they are extremely rare.
    Yes, I do think the transformer was ultralinear, as I recall.
    I have no idea as to the history, except that I think it was developed for Deep Purple ( I read this somewhere...).

    If anybody knows the history of the 6 tube Major, I would like to know.
     
  5. mickeydg5

    mickeydg5 Well-Known Member

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    Are you talking about the 2000 series Lead head? It had 6 6550 with 250W output but that was in the eighties.
     
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  6. proxy

    proxy Active Member

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    fP6rkru.jpg This is schematics as Fusionbear uploaded.



     
  7. danfrank

    danfrank Well-Known Member

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    Not a Major. They were released in 1981 or 1982 and very few were sold. The LEAD version was 250 watts with 6 6550s and the Bass version had 8 6550s and good for 375 watts. The B+ was over 600 volts in these two amps but they weren't in ultra-linear configuration; just standard pentode configuration like the SuperLeads and 2203/04s of the time.

    Here's the lead version schematic:

    https://www.thetubestore.com/lib/thetubestore/schematics/Marshall/Marshall-2000-250W-Schematic.pdf

    Bass version here:

    https://www.thetubestore.com/lib/thetubestore/schematics/Marshall/Marshall-2001-375W-Schematic.pdf

    The preamps in these were pretty versatile.
     
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  8. BowerR64

    BowerR64 Well-Known Member

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    8 power tubes in one box!!?!? jesus

    It came stock with wheels and a back support strap right?
     
  9. danfrank

    danfrank Well-Known Member

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    How about this for mini?!? LOL! One of my 100 watt "PIG" amps in an 18 watt cabinet!

    small2.jpg
    small3.jpg
    small1.jpg
     
  10. neikeel

    neikeel Well-Known Member

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    tce63 likes this.
  11. ampmadscientist

    ampmadscientist Well-Known Member

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    I have worked on a couple 6 power tube majors.
    The B+ was actually more than 700 volts as I recall....
    But Marshall had problems with stability and the amps were prone to motor boating / oscillations.
    (seems like a lot of amps that tried 6 power tubes were unstable)
    The 8 power tube (KT88) bass amp is currently being sold by Hiwatt, a 400 watt most powerful tube bass amp..about $5300.00
    [​IMG]
     
  12. danfrank

    danfrank Well-Known Member

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    I'll have to open it up and take pictures. I was trying to get it built before a trip I took to L.A. so I didn't take pics like I should have. Funny thing is I stopped by at Freidman's shop in North Hollywood and asked them if they'd like to try it out and their reply was, "Oh I'd LOVE to try it out and see how it sounds, but we're SO swamped right now". LOL!
     
  13. ant_riv

    ant_riv Active Member

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  14. mAx___

    mAx___ Active Member

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    Here's my 100w 2xKT88 "Blackmore" Major build. It has my take on the factory mods he did in 1970. I build them for fun and keep them affordable.
    Direct to amp, treble booster is off. Just some reverb added and minimal EQ.
    Blackmore's guitar is removed from the backing tracks.

     
    Last edited: May 8, 2019
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  15. proxy

    proxy Active Member

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    Do you have any more pics of your Mini Major?
    Inside pics?
    Thanks
     
  16. Kats

    Kats Active Member

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    Max, that sound was right on! Definitely unique enough in tone to make it a worthwhile addition.
     
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  17. neikeel

    neikeel Well-Known Member

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    Is this the amp that was being debugged in the thread recently? It certainly seems to nail the Blackmore tone in my head, at least. How close is this to the schem posted by Proxy above? I have a couple of UL transformers (25-30w) that might make a mini-minor-Major, I also have some KT88s, of course whether they are the tubes to try in a lower output version is moot. Just thinking what to do next once my Ormat projects are wound up (oh and the JTM restos!).
     
  18. danfrank

    danfrank Well-Known Member

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    Opened up the amp today, so here you go:

    IMG_20190510_174309.jpg

    IMG_20190510_174153.jpg

    The output transformer is from a Dynaco Mark II and this amp doesn't have the nice treble chime that my other builds have, which use Hammond OTs. This one makes for a better bass amp though.
     
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  19. mAx___

    mAx___ Active Member

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    No, the amp in that thread was a clone of this one, which never had an issue despite being constantly messed with :)
    The schematic above is fairly different than what I have in general. Mine has an extra valve instead of a cascade type of thing. The Major chassis already had an extra hole (for the PA version) and I was told that the factory used it for the mods made to Blackmore's amp. His use of the Bright Channel high sensitivity input seems to confirm this. Also, I tried the Lar/Mar MV but it sounded really bad compared to the attenuator so I removed it. IME this amp needs to be operated as a regular NMV plexi.
     
    Last edited: May 11, 2019
  20. mAx___

    mAx___ Active Member

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    Thank you so much, Kats! :)
     

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