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MC2100 - Advice sought...

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

  1. prelius

    prelius AK Subscriber Subscriber

    Messages:
    499
    Location:
    NorthEast USA
    Folks,
    I recently got a pair of MC2100s. They were used to drive dance floor/stage speakers in a small nightclub. At one point, one of the amps blew the output transistors, so they both of them got taken out of the service and replacement parts ordered. They sat on the backstage rack for many years, and eventually ended up in my basement, including original McIntosh replacement parts and paperwork.
    The problem with these amps is that they have balanced inputs sloppily installed in place of RCA jack (i.e. big holes been drilled out in the chassis); bottom pans are missing; chrome is pitted, and so on... Given their overall current condition, I am looking for comments suggestions on how to proceed with them:
    Particularly, I am considering the following path:
    1. Disassemble the amps; weld the openings drilled for the balanced inputs; re-chrome the chassis; re-apply silk screens; reassemble the amps. I can do the disassembly, and silk screening myself. Chroming will be done by the shop.
    2. Get the replacement bottom covers: either re-make them or try to acquire through Mcintosh or some other 3rd party.
    3.Fix the electronics, bring the amps up, running and tuned.

    So the issue is the cost: I figured re-chroming will cost me about $150-$200 per chassis; re-making the bottom covers - another $100-$150 per amp, repainting trannies - another $100 per amp; other expenses (mechanical, electronic, other parts) - $50 per amp. All in all, it is up to a $1000 worth of repairs. Are these amps worth it? Any other ways to fix the amps? Much appreciate your thoughts and suggestions.

    Thanks, Paul
     

     

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  2. Pio1980

    Pio1980 AK Member Subscriber

    Messages:
    26,556
    Location:
    Angel Station, Alabama
    Clean up, restore electronix, patch hole(s) neatly with chassis hole plugs, or plates if previous opening was altered. Enjoy or sell.
    Anything much further is a labor of love and will have negative investment return for a common, non- unity coupled tube McIntosh example.
     
    maxhifi and nj pheonix like this.
  3. Pio1980

    Pio1980 AK Member Subscriber

    Messages:
    26,556
    Location:
    Angel Station, Alabama
    Also, finding other similarly compromised examples with necessary parts for low investment is your best option.
     
  4. motorstereo

    motorstereo AK Subscriber Subscriber

    Messages:
    10,536
    Location:
    Connecticut
    Given all their problems my advice would be to sell them and use the funds towards some much newer Mac gear. I had a very nice pair of 2100's live here for a few years and they stayed here because of their unique looks......I preferred to look at them as opposed to listen to them if that makes any sense.
     
    Pio1980 likes this.
  5. twiiii

    twiiii Addicted Member

    Messages:
    6,226
    Location:
    west Texas
    I had 2100's for about 5 years, and much preferred my Crown amps that replaced them with my speakers. My woofers bi-amped prefer very high damping factors and Mac amps from that period are pretty sloppy in relation to the Crowns. Some also might say the 2100's and 2200's sound fuzzy. So even If I could do the work as you say you can I would pass. Now if they were 2105's you would have a big chance of getting your money back. Find your self a pair of 7100's or if you want meters 7200's. Theres a big difference. Especially at 4 ohms and 2 ohms. 7104 amps run in stereo are nice as are 7106, and you have either another channel for a center channel or two smaller chnnels for a center and a rear channel.
     
  6. quartersaw

    quartersaw Well-Known Member

    Messages:
    917
    Location:
    Albany, New York
    I have an ugly pair of 2100's that I recapped.
    Still ugly, but GREAT amps!
     

     

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  7. jlovda

    jlovda Things I loved from the 60's and 70's Subscriber

    Messages:
    3,465
    Location:
    NE Ohio
    Terry Dewick made a comment long ago (paraphrasing) that if the unit(s) are in nice cosmetic condition you can almost always get your money back later if they are restored. If they are rusty, etc. you will probably not recoup any electrical restoration costs if you try to sell later. I guess if you do the work yourself its a different story because your out of pocket costs are lower. I personally would try to get the units working with the parts you have and then sell them locally on CL. Spend your time and effort somewhere else. Were you actually thinking of removing everything from the chassis to rechrome? :crazy: Maybe an MC275.....
     
  8. c_dk

    c_dk Addicted Member

    Messages:
    6,246
    Location:
    West Michigan
    It sounds like you have one that works. Do you like the sound?

    Whether it is worth while time wise to restore will strictly be up to you because the resale will be dubious.

    Once i got them up to electrical performance I think a painted top plate with wood sides a dado captured perforated bottom would protect fro high voltage and be the least expensive "custom' cosmetic work.

    I would be tempted to create a pair of truly balanced IC based XLR input boards as well as adding some typical RCAs.....I am sure presently the XLRs are just pin 3 to 1/ground ie not really balanced.
     
    prelius likes this.
  9. prelius

    prelius AK Subscriber Subscriber

    Messages:
    499
    Location:
    NorthEast USA
    Folks,
    Thank you very much for your thoughts, comments and suggestions. While I am a "tube guy" (own and use a pair of MC30s, among other tube amps) I would like to have a McIntosh solid state amp as a SS reference system. While 2100 does fit visually with my MC30s, I am not sure it whether it is representative of MC "solid state" gear. ButI am willing to give it a try, so I think I will keep the working amp for now, and sell/trade the other one.
    Again, thank you again for your perspective and thoughts.
    Cheers, Paul.
    PS. If anyone is interested in a non-working amp, please let me know... :)
     
  10. c_dk

    c_dk Addicted Member

    Messages:
    6,246
    Location:
    West Michigan
    The MC2100 was a part of the seminal series of transistor amps designed by the engineers who designed your MC30s. You could say that they came up with these designs as it became obvious that the supply of tubes would be drying up as most suppliers were abandoning their tube assembly operations and R&D, putting their efforts toward semiconductors.

    So the sound of these early SS units were bench marked against their tube amp designs.

    The typical problem of output failure in these amps was caused by the marginal heat tolerance of the RCA driver transistors and their tendency to run away taking out the outputs and typically burning a few resistors on the driver boards. Mac supplied a kit back in the 80s to upgrade these parts.

    If you have Mac supplied replacement parts you should have these kits.
     
    prelius and Pio1980 like this.
  11. welcomdmat

    welcomdmat AK Subscriber Subscriber

    Messages:
    1,095
    Location:
    Pittsboro, NC
    I really enjoyed my 2100. When the right price came, I sold it. It was a very nice amp to listen to for extended periods.

    I have briefly run two 2100s, and I ran two 754s for a bit which have similar power output. Running two is a lot of power, and I enjoyed one more. I don't know if it had something to do with my gain being set higher or not, but a two amp setup was wasted on me.

    There is certainly a market/ demand for the 2100. I have seen most any in decent shape sell quickly, and ones in poor physical condition move when priced well. The BIGGEST issue with selling a 2100 is shipping. They are heavy, oddly shaped, and proper packing is both heavy and expensive. Buyers balk at high shipping charges, but you have to protect yourself in costs and them in receiving what they expect.
     
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  12. Snappahead

    Snappahead AK Subscriber Subscriber

    Messages:
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    I have (3) 2100's. I happen to like them very much but I don't think the market bears a grand for them. Here's why I say so. I happened to buy mine years ago very inexpensively. I think between $ 3-500 each. Because I have an affinity for them, I had them completely serviced by Audio Classics. One of them cost $ 638.00 for a complete over haul and the cosmetics are excellent. I decided I'd try to sell it so I posted internet ad with a price of $ 1000.00. I didn't get a nibble. They are great sounding amps, built like tanks, and IMO, are cool as hell. But everyone wants those blue meters, hence the 2100's are not desirable.
     
  13. techguy0192

    techguy0192 AK Subscriber Subscriber

    Messages:
    953
    Based on your description, I wouldn't let it go for less than around $1K. I believe, in top condition, they bring around $1100 to $1200 at AC.

    Not true on the meters. I highly prefer the non-meter Macs. Anytime I'm using one with meters, I switch the lights/LEDs off.
     
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  14. welcomdmat

    welcomdmat AK Subscriber Subscriber

    Messages:
    1,095
    Location:
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    I agree with a few things here. I am not a meter guy (my 754s did not have meters either -- part of their attraction). However, I do believe that meters pull more money.

    I have spent minimal time trying to sell my 2100s at $800-$900, and they did not have as much work as you are talking about. If you bring them up to a beautiful, displayable condition, $1000+ a little should not be hard. It seems to me that these were sleepers in the Mc line, but their desirability (price) is steadily on the rise.
     
  15. Snappahead

    Snappahead AK Subscriber Subscriber

    Messages:
    125
    I won't sell mine for less than $ 1000. They are worth that much to me but I don't think they would bring a retail price of $ 1200. I have to disagree regarding the meters. 2105's which are the same amp with meters bring considerably more money.
     
  16. Snappahead

    Snappahead AK Subscriber Subscriber

    Messages:
    125
    I put one out there at $ 1000. Not a bite. I haven't tried anything further because it's not important to me to sell them I'd like to see one or two of them being enjoyed by someone rather than sit on a shelf.
     

     

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  17. shelly_d

    shelly_d Not An Audiophool

    Messages:
    6,608
    Location:
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    Here is an example of a 2100 neatly modded to balanced inputs:
    [​IMG]
    Any chance of redoing the SLR connections to look more like this then what you have?

    If so, then that and bottom covers to get them safe and you have a saleable pair.

    Shelly_D
     
  18. techguy0192

    techguy0192 AK Subscriber Subscriber

    Messages:
    953
    That unit is pretty far away from stock. The only mod I'm okay with is a power switch in the aux power location. Otherwise I feel changing them up takes away from the value and ability to resell.
     
  19. shelly_d

    shelly_d Not An Audiophool

    Messages:
    6,608
    Location:
    Alameda CA
    Probably correct, however the OP's units are already modded (perhaps even butchered from the description). If this becomes a doable mod to clean it up, it might be a viable option for him.
     
    Pio1980 likes this.
  20. Pio1980

    Pio1980 AK Member Subscriber

    Messages:
    26,556
    Location:
    Angel Station, Alabama
    Pix might help.
     

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