My vintage McIntosh MX-110 preamp surprised me today. Follow up post #61!

Discussion in 'Audio Hardware' started by Steve Hoffman, Nov 11, 2011.

  1. sberger

    sberger Dream Baby Dream

    Yes this system came together pretty quickly(over the last 3 weeks). Sounding damn fine.
     
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  2. sberger

    sberger Dream Baby Dream

    My ears are the only performance indicator I trust.
     
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  3. 62caddy

    62caddy Forum Resident

    Location:
    PA
    Nothing wrong with that however the MPI 4 is invaluable in turntable setup.
     
  4. sberger

    sberger Dream Baby Dream

    I've been doing TT setup for decades, and use very simple turntables that are basically set it and forget it. I prefer that after years of expensive, sensitive tt's that required much more effort.
     
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  5. sberger

    sberger Dream Baby Dream

    BTW. if I could find an MPI4 in good shape that was affordable, I'd grab it in a second.
     
  6. 62caddy

    62caddy Forum Resident

    Location:
    PA
    I know in my case the MPI4 revealed the anti skating adjustment was set considerably lower than it should, despite following the instructions of the cartridge manufacturer. It's my guess the A/S spring had lost some of its tension over the years.
     
  7. monkboughtlunch

    monkboughtlunch Senior Member

    Location:
    Texas
    I realize you posted the issues with your muting and eye tube a long time ago and not sure if your tech fixed the issue. But I learned that McIntosh issued a service bulletin modification in June 1966 (112-1). It states "MX110 X and Z series" modification: "this modification eliminates both the opening of the tuning eye after warm up, and the muting threshold change with warm up."

    The modification described in the bulletin may be related to your issues if your MX110 was made prior to mid 1966.

    [​IMG]
     
  8. 62caddy

    62caddy Forum Resident

    Location:
    PA
    Good information but this is a different issue than what the poster quoted is experiencing.
     
  9. fortherecord

    fortherecord Senior Member

    Location:
    Rochester, NY
    Thanks, unfortunately, I've since sold the unit, to my regret now.
     
  10. Walter Koehler

    Walter Koehler Forum Resident

    Location:
    Hamburg, Germany
    Aloha
    lucky me just got another Mc-110 can compare now the X to the Z version and doin some tuberolling for fun
    cheers
    :cheers:
    [​IMG]

    [​IMG]
     
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  11. monkboughtlunch

    monkboughtlunch Senior Member

    Location:
    Texas
    Are they both fully restored and up to spec? How would you characterize the sonics of each series?
     
  12. monkboughtlunch

    monkboughtlunch Senior Member

    Location:
    Texas
    Anyone have a list of critical items in an MX110 that should be replaced during a service for SAFETY reasons?
     
  13. Bill Hart

    Bill Hart Forum Resident

    Location:
    Austin
    FWIW, the repair/service manual is on line and any competent radio/hi-fi repair guy could quickly identify those areas that are critical. I don't have the technical chops, and had mine restored by someone who has regularly worked on the model, Bill Thalmann. I know a lot of people like Terry Dewick (sp?). To me, all of this stuff, a bad wire, an old capacitor, a bad solder joint, could be a hazard, but that's why I don't do my own work (aside from the lack of skill and competence). I do know that there was some work done on the one I bought that wasn't to the level of mil-spec that the old McI gear was known for- so until somebody knowledgeable opens it up, checks voltage at certain test points, and traces some of the wiring--it's a rat's nest--who knows what's in there. PS: it wasn't terribly costly to have the unit restored in terms of labor; the tubes will cost a bit if you are buying Telefunkens for some of the critical spots. Maybe someone else here could give you more specific guidance. Mine was converted from a two to three prong AC cord because there are diodes, I believe, that help in isolating the grounds that often deteriorate, but I may have that wrong. In any case, once my got sorted, it has worked like a champ.
    PS: that post above, with the service update (it looks like you posted it!), is the kind of thing that someone who regularly works on these units should have. I know Thalmann had all that info.
     
    Last edited: Oct 17, 2017
  14. fortherecord

    fortherecord Senior Member

    Location:
    Rochester, NY
    The sélénium rectifier and power supply caps should be replaced to start with.
     
  15. monkboughtlunch

    monkboughtlunch Senior Member

    Location:
    Texas
    Is the power supply update just limited the two silver cans on top and the cardboard can? Did all versions of the "Z" 110 use selenium rectifiers or did they move to silicon in later production? Can you point out the rectifier in the below picture? What part number / model should the rectifier be replaced with?

    [​IMG]
     
  16. Bill Hart

    Bill Hart Forum Resident

    Location:
    Austin
    You are obviously technically skilled and way out of my league, but there is one employee at McI that was there from the old days, as of a few months ago, that knows these units. You could give McI a call and ask. Sorry, I don't know his name, an amp service guy here in Austin called him on my behalf recently regarding a question about the power supply. You have the schematic for the basic unit, right?
     
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  17. Steve Hoffman

    Steve Hoffman Your host Your Host Thread Starter

    Anyone have any adventures with an MX-110 recently?
     
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  18. bresna

    bresna Senior Member

    Location:
    York, Maine
    They are Selenium rectifiers. They are just behind the biggest yellow Sprague capacitor. It looks like 4 stacks of round metal wafers between square pieces of metal. Here's a close up:
    [​IMG]

    When you replace the selenium rectifier you will want to replace the can caps because the silicon replacement diodes supplies more voltage, stressing the old caps..

    Here are a couple of discussions on how to replace them: MX110Z Selenium Rectifier
    and: Recap parts list for an MX-110 Z??

    While you are in there, be sure to add a CL70 thermistor to slow down the turn on time. The thermistor (the black disc seen below) is installed in the main AC feed:
    [​IMG]
     
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  19. monkboughtlunch

    monkboughtlunch Senior Member

    Location:
    Texas
    Howdy Steve:

    Here's an adventure that The Doors had with the MX-110 back in 1968!

    I noticed some gear when watching the Doors documentary "When You're Strange."

    Below is a scene filmed circa 1968 at The Doors' beach house (or Krieger's house?). That's Robby Krieger on the left.

    I spotted the following and noted them in the screen grab below.
    • McIntosh MX-110
    • Thorens TD-124
    • Dual 1019
    I couldn't identify the reel to reel. Anyone know that model?

    [​IMG]
     
  20. Steve Hoffman

    Steve Hoffman Your host Your Host Thread Starter

    More than one turntable? Odd for that time.. Old Sony R2R? Not a great one.
     
  21. Subagent

    Subagent down the rabbit hole, they argue over esoterica

    Location:
    Arlington, VA
    But the cinderblocks and boards are right on the money for 1968!
     
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  22. Steve Hoffman

    Steve Hoffman Your host Your Host Thread Starter

    Yup, and well into the 70's!
     
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  23. monkboughtlunch

    monkboughtlunch Senior Member

    Location:
    Texas
    Looks like a 78 RPM record is sitting next to the Dual 1019. He probably used the 1019 (a record changer) to play 78s, and used the TD-124 for LPs and 45s. He was putting the MX110’s 2 phono inputs to use.
     
    Last edited: Aug 15, 2019
  24. Bill Hart

    Bill Hart Forum Resident

    Location:
    Austin
    I only recently started using the phono stage in mine since I was armless for a while after I got the unit back. Bill Thalmann did the resto, and for the MX110z, supplied the tubes- in the phono slot, NOS Mullard 4004. (I was concerned those might sound syrupy, but they don't in this system; at some point, I can throw some NOS Teles in, I usually only keep ribbed, rather than smooth plates, b/c i use them in my amps upstairs). This is part of the vintage system downstairs.
    [​IMG]IMG_0999 by William Hart, on Flickr


    [​IMG]IMG_0998 by William Hart, on Flickr
     
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  25. Steve Hoffman

    Steve Hoffman Your host Your Host Thread Starter

    Yup, that is what I would have done. I wonder what 78’s he had? Benny Goodman? Fats Domino? Blind Lemon Pledge?
     
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