Need To Build Another Amp

Discussion in 'Building the Classics' started by bluesky636, Jan 27, 2020.

  1. bluesky636

    bluesky636 Member

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    I am retired and build vacuum tube guitar amps as a hobby. To date I have built a 5F6A Bassman clone, a Trainwreck Express clone (played through a Marshall 1960a Lead cabinet loaded with G12M-65 Creambacks), and a 5F1 Champ/5F2A Princeton hybrid. I have also modified the Fender Champion 600 reissue to 5F1 spec and the Fender Blues Deluxe Reissue to closer to 5F6A spec.

    I now want to build a Marshall clone and am trying to decide between a JTM45 and Plexi. The amp will be played through a Crate 4x12 cab loaded with Celestion G12M-25 Greenbacks. So my question is, which of the two Marshall's I mentioned would sound different from, yet would compliment the amps I have already built?

    Note that i only build Weber kits and I make modifications to each to tweak them to my tastes. Also, i have a BSEE earned when vacuum tubes were still part of the curriculum.

    TIA.

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    Last edited: Jan 27, 2020
  2. MarshallDog

    MarshallDog Well-Known Member Premium Member

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    Nice Brother MFr! I am an EE also BUT more on the electronics side. Never built an amp but would love to!
     
  3. South Park

    South Park Well-Known Member

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    Solder junkie hack hear I would build a jtm 45 with a cascade 2204 gain stage . That gain with some voltage sag
     
  4. bluesky636

    bluesky636 Member

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    My specialty was SATCOMM systems engineering as a contractor for a three letter Federal Government agency. :D
     
  5. bluesky636

    bluesky636 Member

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    Already have one high gain amp.
     
  6. Micky

    Micky Well-Known Member VIP Member

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    Nice to see a tweed Champ
     
  7. junk notes

    junk notes Active Member

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    Difficult to answer. Do you know what a Plexi is?

     
  8. bluesky636

    bluesky636 Member

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    Yes. I know what all the amps I build are.
     
  9. South Park

    South Park Well-Known Member

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    So what sound are you looking for . How do you like that train wreck
     
  10. bluesky636

    bluesky636 Member

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    Since a JTM45 is a 5F6A with different tubes, I think I will just build a Plexi.
     
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  11. Peter McAteer

    Peter McAteer Active Member

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    FDA? :)
     
  12. guzzis3

    guzzis3 Active Member

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    That was what I was going to suggest. And a lead circuit not a PA or bass.
     
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  13. Gunner64

    Gunner64 Well-Known Member Premium Member

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    Since you mentioned weber kits and Marshall in the same post...I have a 6m45p weber kit and I would not recommend that "Marshall clone" kit. It Sucks.

    My reasons, Shitty pots, jacks, wiring, not up to classictone quality transformers. They don't use the traditional vintage Marshall style turret board but a fender style tag board.

    What really pissed me off about this ill conceived package was the filter cap board..yes it doesn't have cans it has a board, like a fender, but with like 15 caps Frankestiened together on it. The problem here is this whole stupid board needs to be mounted on the studs of the powertrans, and with the main board in, in their supplied chassis the 2 boards don't fit, not even close. This oversight is huge, and Totally unacceptable. Why do this when 3 fucking cans will suffice in a simpler set up? I ended up shit canning the cap board, and going with 3 cans instead.

    Bottom line You get what you pay for here. There's a reason the 6m45p kit is cheaper than the other kits. I got this kit with tubes, chassis and smallbox headshell for $400 unbuilt. if I would have paid full price I would have been really pissed off, and it would have went back..but by the time I upgraded the pots, jacks, caps ect. I could have sourced parts and had a better quality amp. Live and learn. The good?..nice ply headshell, and after a few tweaks sounds pretty good.

    Your results may vary. But my experience with this kit here is what it is.

    Fyi This wasn't my first build, I had may under my belt before I built this. I was just amazed at the oversight in design here, with the boards not fitting in the chassis. and cannot reccomend the 6m45p kit to anyone.

    With your experience I would find a layout, source parts, and build my own.. I would suggest an 18w tmb..

    Nice builds there by the way!
     
    Last edited: Feb 5, 2020
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  14. bluesky636

    bluesky636 Member

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    I don't have a problem with the Weber kits and their parts but I also wasn't impressed with the power supply cap mounting for the Marshall clones.

    I decided to build a Weber 5E8A Tweed Twin as a head and run it through my 1960A Lead cab (loaded with 16 ohm Celestion G12M-65 Creambacks) set to 4 ohms. I currently run my Trainwreck Express clone through this cab so I'll plug that back into my Crate 4x12 cab that is loaded with 16 ohm Celestion G12M-25 Greenback reissues.
     
  15. Gunner64

    Gunner64 Well-Known Member Premium Member

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    Yea, The Weber Fender kits maybe different, I have no experience with them. I was just commenting on the their 6m45p kit.. which is supposed to be a Marshall clone. The intended parts did not fit in the supplied chassis following their layout. The power trans mounting correlation was wrong, as the short side faced the boards in actuality, where in the drawings the long side...which meant that the power trans + the 2 boards were too long for the chassis..huge oversight.
     
  16. Chris-in-LA

    Chris-in-LA Well-Known Member

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    I built the Weber tweed Super, quality was definitely lacking, transformers were cheap Chinese stuff. The PT was noisy and caused weird oscillations the were resolved when I installed a Mercury Magnetics PT.

    Here’s a visual comparison of the two transformers that were supposed to be the same specification. The Chinese Weber is on the left. I’m not necessarily a MM fanboy as I find that ClassicTone iron works great at a fraction of the cost.
    2B13E879-606F-4D95-B1CE-FA86BF9A88D0.jpeg
     
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