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MC240 Restoration

Discussion in 'McIntosh Audio' started by dingo1670, Jun 1, 2018.

  1. dingo1670

    dingo1670 New Member

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    Hello Fellow McIntosh fanatics! I am currently working on Restoring my first MC240. I have already gone through the PS Section and am currently measuring all of the Carbon Comp resistors and Capacitors. There is some debate o whether to leave the Red Lettered .22uf 600V Black Beauties in or not. I am measuring mine and they're coming back at around 1uA of leakage @ 600V. What value is considered not acceptable?
    I am being advise that given their age, I should replace them as the Caps are now over 55+ Years Old! I would replace with a combination of Orange Drops and Russian K40Y Capacitors. Thanks for your feedback in advance!
     

     

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  2. Pio1980

    Pio1980 AK Member Subscriber

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    If you go all-out, check with Jim McShane about a signal path recap kit.
     
  3. dingo1670

    dingo1670 New Member

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    Yeap! Already did my friend.
     
    Pio1980 likes this.
  4. dingo1670

    dingo1670 New Member

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    Yeap! Already did my friend. Jim is a great guy and he's been a wealth of help! I have a lot of his parts to work with on this project. Thank you.
     
    Pio1980 likes this.
  5. UncleBingo

    UncleBingo AK Subscriber Subscriber

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    I think Terry DeWick leaves those in there iirc. He makes zero commission on the parts he doesn't sell you! : )
     
  6. Pio1980

    Pio1980 AK Member Subscriber

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    Terry afaik leaves the 160P as did I. I did not check them myself for leakage, taking the opinion of my predecessors.
     

     

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  7. dingo1670

    dingo1670 New Member

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    Well I do have 2 of these puppies to do, so maybe what I'll do is a little comparing. I'll change those particular caps on one unit and leave in on the other. I'll do some listening tests and see how different they sound. If the sound is comparable, I'll change them on both given the age of the caps. Eventually I'll be running these in Mono mode, so I want them to be close in sound for obvious reasons.
     
    Pio1980 likes this.
  8. BillWojo

    BillWojo AK Subscriber Subscriber

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    Sounds like a great plan. I wonder if 50+ year old caps sound like new or just different? Some folks say they like the "sound" of vintage components but I wonder what they are really hearing.

    BillWojo
     
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  9. nj pheonix

    nj pheonix AK Subscriber Subscriber

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    I'd like to hear your impressions .
    Keep in mind if you go with the Jim McShane parts you'll have several Russian PIOs .
    They take some time to break in.
    You may want to wait a few dozen hours
    (Perhaps a hundred or more)
    Before you A B
     
    Pio1980 likes this.
  10. Pio1980

    Pio1980 AK Member Subscriber

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    I still have the original Good-All film caps in the 'direct' signal path of my Marantz 8, the high pass path caps are replacements. I don't listen thru the high pass. I really can't say about the total sound signature of the amp re the original caps vs replacement, but the measurable static state characteristics of those vs a "perfect" cap like a Teflon example can be determined.
     
    dingo1670 likes this.
  11. dingo1670

    dingo1670 New Member

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    You're right, I think it would be better to let them settle in a bit before making a judgement call. Good call!
     

     

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  12. dingo1670

    dingo1670 New Member

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    I was wondering the same thing and so have others I guess. Did the Amp sound like it does when it was only a couple of years old?? Or do the aging of the components somehow change the sound signature to our liking?? That's a tough one!
     
    Last edited: Jun 1, 2018
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  13. Pio1980

    Pio1980 AK Member Subscriber

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    Assume we are saying for component parts that hold measured value but are aged under working cdx.
     
  14. x3workshop

    x3workshop AK Subscriber Subscriber

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    I have a pair I run in mono with the original 160P caps in them. I left them in based on Terry D's statement that they're rarely bad. Well, since I got a real cap tester, I've tested many other 160Ps and almost all leak to various degrees. I intend to change mine for K40Y.
     
  15. Pio1980

    Pio1980 AK Member Subscriber

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    I wonder if they may be "ageing out" years after Terry made the determination. The problem would be with the leakage shifting the operation points of the various stages in which they are used.
     
    Bill Ferris likes this.
  16. dingo1670

    dingo1670 New Member

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    Just picked up some 40Y’s and tested them all for leakage even though they were never used. They all had some, but what I would consider very minimal and accaptable
     

     

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  17. dingo1670

    dingo1670 New Member

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    BFF1EDEE-BF73-4A3D-ABC0-E67DE2059E17.jpeg
    Well I’ve successfully completed my complete Re-Cap and Resistor changes on both of my MC240’s. I replaced the Caps with K40Y’s. It really wasn’t bad at all. I tested everything as I went along. During my restoration I picked up a very nice MX110Z, and so this evening I was completely blown away by this marriage! I believe I have found the Audio Nirvana I have been in search of for so long. I mean WOW!!! It’s simply incredible with what I am hearing with these MC240’s and the MX110Z. Glorious
     
  18. techguy0192

    techguy0192 AK Subscriber Subscriber

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    Those 240s look mint. :thumbsup:
     
  19. damacman

    damacman Blown and Injected Subscriber

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    Bridged MC240s was a great combo for me! I ran that in the '90s for a while. You guys are having way too much fun.
     
    CruzBay, x3workshop and Pio1980 like this.
  20. Pio1980

    Pio1980 AK Member Subscriber

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    These things are nice to service, enjoy your reward!
     

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