MC2100 - Advice sought...

Discussion in 'McIntosh Audio' started by prelius, Jul 10, 2018.

  1. BillWojo

    BillWojo AK Subscriber Subscriber

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    Yea, agree with Pio. Let's check these out. By the way, I'm another one that really likes the older Mac styling and doesn't need meters, I find they are to distracting.
    I think if I was to ever bi-amp my Altec's, it would be with my MC40's and a single MC2100. Would look pretty cool all lined up with the MC2100 in the middle.

    BillWojo
     
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  2. prelius

    prelius AK Subscriber Subscriber

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    Folks,
    I am attaching a few pix... As I mentioned, it is in a poor shape and needs some major work done...
    Cheers, Paul.
     

    Attached Files:

  3. techguy0192

    techguy0192 Well-Known Member

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    That unit has a lot of cosmetic issues and deviations from stock form. Honestly, it's not worth much. For McIntosh, condition is everything because everything on them is repairable with good parts availability from McIntosh. Use it as a repair learning opportunity. Otherwise, this would be a parts only unit in my opinion.
     
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  4. Pio1980

    Pio1980 AK Member Subscriber

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    These are parts donors, or a Labor of love entry to McIntosh power amp ownership. As long as the transformers are good, they can be revived.
     
  5. c_dk

    c_dk Addicted Member

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    I will confess....in 193=73 i went the for a pretty metered MC2505 instead of a blue colar Mc2100......

    The MC2100 was the workhorse mac amp from driving shaker tables to PA systems they were the pickup truck amp v. the sporty Mc2105.....

    Because they have so many cosmetic issues they would be a great basis for a modern interpretation of a comercial redesign.

    I would copy the input stage of a MC7300 to adapt this to a true balance input......making use of the NE5532 opamps to create the differential input for the balanced input but also a true inversion circuit to allow the amp stages to be bridged.

    A IEC power cord receptor, illuminated power switch and would certainly ground the chassis to insure no chance of a "hot' mic.....forget chrome a industrial hammertone would complete the no nonsense commercial design.

    The board pictured has some real shortcuts......many MC2300 amp threads here in the forum contain the correct updates to these boards.
     
  6. maxhifi

    maxhifi AK Subscriber Subscriber

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    I would clean this up the best you can, and make it work. Can you do electronic repairs yourself? The components won't cost an arm and a leg, transistors and passive components are fairly generic and cheap. I'm not entirely sure it would be worth it to pay a tech to bring them back to perfect, but if you know your way around amps, and the transformers are all good, it should be a fun weekend and not much investment in parts to bring them back to stock working order.

    As for cosmetics, I agree with others that a "frame off" restoration as you propose is not really going to pay back. If these were mine, I would blow them out really well with compressed air, and then wash the outside surface with warm soapy water and a cloth. Then rinse and dry with compressed air. You could take steel wool to the worst of the corrosion, tidy up the modifications and cover the holes, and then just use them.

    In the old days, a lot of people would house "basic amps" like these in inconspicuous hidden locations, so they could be heard but not seen, leaving the preamp as the visible part of the system. Maybe if you get them working well, then this is the way to go?
     

     

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  7. arts

    arts Super Member

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    Amplifiers are like horses; pretty is as pretty does. Personally,I see this as nothing more than the patina acquired after a lifetime of dedicated service,and other than a good cleaning and electrical checkout,with repairs and updates as necessary,I'd leave her as she stands.

    My own MC2100 spent a few weeks in the flooded basement of a recording studio that had a fire,then rode from the other end of Canada to me thrown in the back of a pickup truck,exposed to the elements the whole way.It looked only slightly less shitty than yours.I cleaned it up,effected some minor repairs,and proceeded to use it for many years.She expired (finally!) a while back,and is now in my ''to do'' pile.:)

    I'll tell ya,the looks on people's faces when they spotted (and heard!) my old Mac rotbox running as my daily driver were priceless.
     
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  8. BillWojo

    BillWojo AK Subscriber Subscriber

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    I agree with both maxhifi and arts, if you have the skills just fix them up and run them. My MC40's will never win a beauty contest but they beat out all of the tube amps I've compared them to on my Altec's. That's good enough for me.
    If they were in perfect shape when I found them I could have never afforded them in the first place. Consider yourself lucky to be a Mac owner with the low entry price.

    BillWojo
     
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  9. MACKIE1975

    MACKIE1975 Well-Known Member

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    Labor of love. Amen
     
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  10. damacman

    damacman Blown and Injected Subscriber

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    Not to get too far off topic, but I’d be interested in learning more about this Chris. Specifically - if one uses the MC7300 (or MC2600) bridged via XLR input, is the amp balanced from input to output?
     
  11. c_dk

    c_dk Addicted Member

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    GRRRHHH..........Tony starts channeling Tim Taylor......More Power!!

    3:00 AM and you are making me think, damn meds.

    To me balanced in audio means long microphone runs with a 100 % foil shield for maximum shielding and rejection of common mode interference(RF). The morffing of TRS 1/4 inch phone plugs and Cannon XLRs to inter amplifying stages was a natural progression due to harsher RF interference environments (who all remembers outlaw CBs) and bonded ground planes. (hot mics come to mind)

    I think that any amp used in bridged mode would step on McIntosh's new marketing slogan of balanced from in to out IF they are not using a differential amp to create a balanced difference signal from a common ground signal but are accepting a balanced input from the previous stage.

    What amp was their lead product for this marketing slogan? Lifting the autoformers reference to chassis ground might be the final step to "combine" the two differencal signals in the autoformer. Could this development be a end around further IEC bonding regulations.

    Anyway a rough MC2100, with the badges of blue collar performance out in the field could be a interesting basis for further development just because it ain't purty for the obsessed collector class.

    Now back to boning up for this weekends project, taking apart a pair of Quad EL57s.
     
    Last edited: Jul 13, 2018
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  12. miketuason

    miketuason Ferrari & McIntosh

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    AC9C31BA-147C-4BBD-9A0C-5980C88BAB8E.jpeg
    Sorry for bad photo
    2100 are great amps specially if bridge to mono.
     
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  13. arts

    arts Super Member

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    But only if you have a shelf that can support a pair of them:)
     
  14. motorstereo

    motorstereo AK Subscriber Subscriber

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    They're also great for holding down a pair of MC2500's so a stiff breeze doesn't knock them over:)
    1462628127138 (1).jpg
     
  15. quartersaw

    quartersaw Well-Known Member

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    I'll never sell my two 'beater' Mc2100's, because I love them, and I'd never recover the rehab costs anyway. :)
     
  16. welcomdmat

    welcomdmat AK Subscriber Subscriber

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    Those are some well made stands!
     

     

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