McIntosh MC275 issue. Tube popped. Distortion now audible... Thoughts?

Discussion in 'Audio Hardware' started by Wired4Fun, Apr 1, 2018.

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  1. Wired4Fun

    Wired4Fun Forum Resident Thread Starter

    Location:
    Cary, NC
    For reference, this is a 2017 model MC275, about 8 months old.

    So, I have a tech coming out this week, but thought I'd ask here for ideas...

    I was playing a record yesterday, when there was a flash, a pop, and my MC275 amp went into "Oh God, oh God, we're all going to die", mode. #serenity

    The 3 SMALL tubes on the right (if looking at it head on, viewing the badging) turned red and blinked on and off, until I shut down the rig.

    I turned on the rig after a bit, and all seemed fine, EXCEPT there was now distortion in the right speaker. No matter the song, when sound came through, along with it came a buzzy/distortion. I though my speaker was screwed, so I swapped the L/R cables, and lo and behold, the problem transferred to the other speaker. Clearly not a speaker issue, thankfully.

    From here, I went to my AV shop, and they determined it was likely the two KT-88 tubes on the right side. They gave me replacements, I went home, swapped them out... Still the problem is there.

    Buzzy distortion that, if I swap the speaker cables, transfers from one speaker to the other. This SEEMS like an amp issue, but could it mean I need more new tubes? Is it possible something in the amp fried, despite its SENTRY protection blah blah blah?

    Anyway, I'd appreciate thoughts very much, and while I am here, a Happy Easter and Happy Passover to those who celebrate :) Thanks in advance for your assistance!
     
  2. Wired4Fun

    Wired4Fun Forum Resident Thread Starter

    Location:
    Cary, NC
    I should also add, the source does not matter. Vinyl, digital... always the distortion.
     
  3. allied333

    allied333 Audiophile

    Location:
    nowhere
    Red plate tubes indicates loss of tube bias voltage.
     
    McLover likes this.
  4. McLover

    McLover Senior Member

    Yes, I think you have a bias voltage issue. Call McIntosh and see what they suggest.
     
  5. Dennis0675

    Dennis0675 Hyperactive!

    Location:
    Ohio
    Yikes! I’d say an internal part of the amp has failed. Something substantial, I’d lobby for a replacement vs. a repair.
     
    Helom likes this.
  6. Wired4Fun

    Wired4Fun Forum Resident Thread Starter

    Location:
    Cary, NC
    Thanks for this info... I am confident that the store/McIntosh will take care of it. I am disappointed it happened, though. Still, any ideas on how serious it could be, given that the system still works... just with some distortion in one channel. I find the whole thing confusing, tbh. :(

    Are you all of the mind that this is a "send for repair" or replace it altogether, issue. No quick resolve?
     
  7. KT88

    KT88 Senior Member

    It has likely had a resistor fail on the internal circuit board. It may also have other tube issues if there is no other component damage. Best to test all tubes. Then have the amp repaired if no tubes are found at fault. Never operate an amp again after failures occur without servicing.
    -Bill
     
  8. Wired4Fun

    Wired4Fun Forum Resident Thread Starter

    Location:
    Cary, NC
    Thanks for this! As it is SO new, do you think it is reasonable to request a replacement vs a repair, or is that silly...
     
  9. KT88

    KT88 Senior Member

    That's unrealistic. You've used it for 8 months. It'll be the same repaired as new.
    -Bill
     
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  10. Wired4Fun

    Wired4Fun Forum Resident Thread Starter

    Location:
    Cary, NC
    Cool. Appreciate the honest feedback :) Now, to deal with the awful 1st world problem of not having a stereo to enjoy for a while... Also, the fear that i should just trade it in and get a solid state amp. LOL
     
  11. The FRiNgE

    The FRiNgE Forum Resident

    A factory repair will be guaranteed, and most importantly by someone who knows how to solder, good as new. Most independent techs are good at troubleshooting, but wield dirty irons and are lousy craftsmen!
     
  12. KT88

    KT88 Senior Member

    Many are such klutzes but some are very good. I have seen some work done by previous owners, customer work, and by other techs, that I would have to refer to as being butchered.
    -Bill
     
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  13. Dennis0675

    Dennis0675 Hyperactive!

    Location:
    Ohio
    I’d still ask for a replacement. We are talking about a very expensive amp. Some above and beyond customer service is what a premium brand is all about. A couple weeks of down time after that kind of investment and only 8 months of use would hurt my feelings.
     
    Helom likes this.
  14. Wired4Fun

    Wired4Fun Forum Resident Thread Starter

    Location:
    Cary, NC
    I agree, it is upsetting. I also feel that "things happen". I can likely send mine for repair, and have my local shop give me a store model (they have a few) to play with in the meantime. It's disappointing, but I want to be fair, too. I am thinking a loaner will be the solution for this piece of the puzzle. ;)
     
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  15. allied333

    allied333 Audiophile

    Location:
    nowhere
    What is the warranty? It may be one year.
     
  16. Wired4Fun

    Wired4Fun Forum Resident Thread Starter

    Location:
    Cary, NC
    3 year warranty. PLUS, a local dealer that would do the right thing, regardless. No worries in this department.
     
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  17. Dennis0675

    Dennis0675 Hyperactive!

    Location:
    Ohio
    A loner for the down time would make me feel better. One would hope that to be another reason to have a good relationship with a local shop.
     
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  18. KT88

    KT88 Senior Member

    Indeed. It would be selfish to expect that a company could afford to hand out free gear just to satisfy the OCD in some of us. Every amp was built by having these components soldered into them. They can be repaired the same way in most every case, with the only downside being some inconvenience. That's what the premium is for, the warranty service. It should not suggest free gear for life.
    -Bill
     
  19. Wired4Fun

    Wired4Fun Forum Resident Thread Starter

    Location:
    Cary, NC
    The thing is, I use this room EVERY DAY. It is really my sanctuary. Silly as this sounds, if it were working, I would be in there RIGHT NOW. So my "routine" is thrown off a bit when I can't sit, listen to music, and chill. Oh well. :( Soon it shall be fixed. Again, thank you all for the feedback!
     
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  20. KT88

    KT88 Senior Member

    That's a likely result of being a good customer for a local shop dedicated to their customers. It wouldn't hurt the OP to take it as a lesson in what tube amp ownership can entail and to even look into buying a SS amp as a back-up.
    -Bill
     
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  21. Wired4Fun

    Wired4Fun Forum Resident Thread Starter

    Location:
    Cary, NC
    I may take it as a lesson to just buy a solid state amp and move on while my 275 has most if not all of it's trade in value. LOL. Love the sound, but I am not sure this is for me. Or maybe I am just disappointed.

    And yes, I have been a loyal and good customer at my local shop, having built a full 4K/Atmos home theater and a dedicated listening room at my home. they take very good care of me, and I of them with referrals :)
     
  22. Dennis0675

    Dennis0675 Hyperactive!

    Location:
    Ohio
    I get your point point but a $6,000 amp failing after 8 months of service should not be part of the compromise for running tube equipment. And it isn’t. Sure, heat, low power, some amount of noise and having extra tubes on hand is to be expected but not ditch city on Easter Sunday.
     
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  23. Wired4Fun

    Wired4Fun Forum Resident Thread Starter

    Location:
    Cary, NC
    I agree, again. I don't think ownership of a tube amp is some agreement to expect failure after 8 months, or failure OFTEN. Not what I have been told by many here, and of course by my local store. Some degree of incidents and tradeoffs, SURE. But not consistent or regular issues, and an expectation of failure around every corner.

    I also don't think that is what KT88 meant, though :) Just that tube amps are finicky, and have issues. I won't speak for him, but that is how I read it.

    The more I type this, the more I may just get a solid state LOL
     
  24. Dennis0675

    Dennis0675 Hyperactive!

    Location:
    Ohio
    And you could trade a Porsche for a Honda to get greater reliability.
     
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  25. Bob_in_OKC

    Bob_in_OKC Forum Resident

    Location:
    Dallas, Texas
    My Audio Research CA50 burned up a resistor (after many years, not during the warranty period), so I bought a backup amp. I was initially tempted to buy a new Topping TP60, which I still think would have been a good idea. I instead bought a used amp that I could resell for about what I paid.
     
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