Nad - The Legendary 8100

Discussion in 'Marshall Amps' started by Edokter, May 11, 2019.

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  1. Edokter

    Edokter Member

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    Just picked this 8100 (the top one) up for a decent price. Everything works, some loose and scratchy pots, that's it. It's a bit of a fixer-upper, and I plan on restoring. I already like how you can break up the clean/crunch, and with humbuckers, you can make really the OD channel growl. I shall post updates on it's restoration.

    [​IMG]
     
  2. Mitchell Pearrow

    Mitchell Pearrow Well-Known Member

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    HNAD congratulations brother please enjoy and share your progress! Cheers Mitch
     
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  3. Edokter

    Edokter Member

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    I had a first glance within. Nothing out of the ordinary. I found a new JJ tube though, but it resisted when I tried to pull it out. I see bent pins on the tube, en bent contacts in the socket. It has been serviced before... by a butcher.

    So first order of business is order replacement parts; some pots, knobs, jacks, capacitors, and a new tube socket.

    Tube socket small.jpg
     
  4. wakjob

    wakjob Well-Known Member

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    Sweet man. I have one, and the 8080 combo version.

    Totally agree on the clean/crunch channel dimed.
    Great classic rock tone. That channel's pathway doesn't use the tube either...all SS.

    I see the vs100 from the second series in your pic.
    I've only read that the clean/crunch on that one actually uses the tube, and is the favored channel for that amp.

    It will be interesting to hear your comparison when you get the 8100 up to snuff.
     
  5. Edokter

    Edokter Member

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    The tube is used on all channels on the VS100. Where the 8100 has the tube placed in the OD channel itself, in the VS100 the tube is actually placed after the FX loop, where it drives the OD tone stack. It uses a slightly weird switching scheme to swith between the clean and OD tone stacks.
     
  6. Robert Herndon Project

    Robert Herndon Project Well-Known Member

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    Yes!
     
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  7. Edokter

    Edokter Member

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    Got the parts. When thery're in, I'll be testing all the pots, and replace where needed. I noticed several nuts missing from the pots, so I hope I can source them separately (M7 brass).

    8100 parts small.jpg
     
  8. StratoMarshall

    StratoMarshall Well-Known Member

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    HNAD! Enjoy!
     
  9. anitoli

    anitoli Well-Known Member

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    I bought an 8100 new when they first came out and the missing nuts are a factory thing. They weren't there on the one i had either. Didn't cause any issues i could see.
     
  10. Edokter

    Edokter Member

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    Good to know! There is a second plate behind the faceplate that does have all the nuts. This saves me a little bit a trouble.
     
  11. 67Mopar

    67Mopar Well-Known Member

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  12. Edokter

    Edokter Member

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    All done! Not much action pics here, but I'll show the end result. All power caps replaced, new tube socket installed, and the tube power supply (two resistors and a diode) replaced... after I ripped off a resistor trying to remove the dried-out hot snot holding the caps in place. Also reflowed all the heavy components and replaced three pots that were quite noisy. I ususally replace those instead of trying to clean them, because I never know how long that will last.

    I like how the pots are mounted to the PCB. Apart from the pins being soldered to the board, all the potshafts are mounted on a separate plate which in turn is mouned to the board with pop rivets. So there's no chance any of the soldering joint will fail. Very sturdy design.

    I ususally repair digital stuff at work, so working on good old fashoined through-hole stuff is a welcome change. I think I might open a little shop for repairing vintage solid-state stuff as a hobby.

    8100 front small.jpg 8100 back small.jpg 8100 inside 1 small.jpg 8100 inside 2 small.jpg 8100 inside 3 small.jpg
     
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