Is anyone familiar with this replacement C28 potentiometer?

Discussion in 'McIntosh Audio' started by Ricktptman, Mar 31, 2018.

  1. Ricktptman

    Ricktptman There are two kinds of Music: Good & Bad-Ellington Subscriber

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    I should've specified "Volume" in the header. But I figure most folks will know that's what I'm asking about. I saw this on Epay. # 152942282464
    I have a few "smallish" issues with mine. They're not as crazy/egregious as some I've read about, but I'm interpreting it to mean that eventually this pot (how do you tell if it's an original or has already been replaced?) will eventually have to be replaced. Thanks in advance for any helpful advice...
     

     

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  2. Ricktptman

    Ricktptman There are two kinds of Music: Good & Bad-Ellington Subscriber

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    Is replacing the "can" on the back of it (with the original) just for appearance's sake or is it necessary to shield the signal from outside contamination? I'm not looking forward to this, but I'm not going to wait for the situation to worsen. I like not being surprised with a different preamp every time I turn it on.
     
  3. c_dk

    c_dk Addicted Member

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    Looks like the generic one you get from Mac parts if you order one from them. The original CTS loudness tap was at 60/40 as was the Alps Mac supplied in the 80s.

    Currently Mac is having the replacement made in Canada.
     
  4. Ricktptman

    Ricktptman There are two kinds of Music: Good & Bad-Ellington Subscriber

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    Thanks, c_dk. I knew you'd be able to shed some light.
    Is it a good replacement, or just "a" replacement?
    I read a lot about some of the replacements having channel balance issues. Is there anything I should watch out for when installing it? Thx..
     
  5. c_dk

    c_dk Addicted Member

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    I would stick with what's in your unit until it has real issues and then get what you know Mac's engineering has oked.
     
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  6. Snappahead

    Snappahead AK Subscriber Subscriber

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    If it's the Mac replacement, don't bother. Bought one for my C 28 and it was a disaster. When I wired it, it ran in reverse. Loud to soft clockwise. I wired it in reverse and the same thing happened. Ended up sending my original to AC's and they rebuilt it for me.
     
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  7. Ricktptman

    Ricktptman There are two kinds of Music: Good & Bad-Ellington Subscriber

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    Thanks to everyone for their responses. Snappahead, I read your posts about this on another thread. My old volume pot (not sure if it's an original or if it's been replaced once already) isn't as "Schizo" as some I've read about. The right channel is dead solid, all "sane" all the time. The Left channel is the (not end of the World) problem. If you turn the volume all the down (to the second hash mark, where the "click" lands it after turn on) I can occasionally hear just a bit (or occasionally more than a bit) of audio leaking through. If I turn it up, the channels will balance and it's NBD. (So it's only a dealbreaker if you're OCD. Unfortunately, that's a pretty good description for me, even if it's not debilitating-audio is where I short it to ground.) IF I stress the knob shaft to the right slightly, the low-level signal will disappear with a soft thump and everything is right as rain for a few weeks until it starts again. I've thought about going in and cleaning it again. I Deoxit-ed it when I took possession of it. But from what I've read since, doing that repeatedly can make things worse, not better. An odd duck, this widget. I've got one of these "non-Mac" pots on the way. I'll post my findings once I've installed it, but it might be a bit before it gets here and I get a chance to get into it.
     
    Last edited: Aug 20, 2018
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  8. Snappahead

    Snappahead AK Subscriber Subscriber

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    Mine started out with an intermittent issue at first. Scratchy, dead spots, etc. I cleaned it and nursed it along until it just didn't work. I hope you have better luck with your replacement. Mine was awful. The tech at AC's sent it back to me and told me to return it to McIntosh because it was junk. They were able to rebuild my old one thankfully.
     
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  9. Ricktptman

    Ricktptman There are two kinds of Music: Good & Bad-Ellington Subscriber

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    I meant to ask earlier: Is there a way to distinguish (by its appearance) an original from a later Mac replacement?
    The preamp seems like a low hours, reasonably well cared for unit. At first, I thought it might be a power supply problem. But as time passed, it seems more closely associated with this volume pot.
     
  10. Ricktptman

    Ricktptman There are two kinds of Music: Good & Bad-Ellington Subscriber

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    BTW, I did get it straightened out. Seems to be fine now. Third time's the charm. Apparently...thx again to all who responded. It just needed a little attention I guess.
     

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