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Yamaha A-960II heat questions

Discussion in 'Yamaha' started by 201bk, Aug 5, 2018.

  1. 201bk

    201bk New Member

    Messages:
    35
    Location:
    Poland
    Hi guys, so my Yammie gets hot, like reeeally hot. I've been thinking it's time to give her a proper service and repairs and all but anyways are there any users here who use this amp and can confirm their amps have high temperatures too? Or is it my thing only? What if I will service it and it will still have heat problems? Maybe it's this AB class I've been reading all about back in the day or maybe something is not right - tbh I'm not really sure if A-960II is an class AB amp. Also it's summer time so there's that.
     

     

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  2. mbz

    mbz AK Subscriber Subscriber

    Messages:
    2,089
    Location:
    Melbourne, Victoria
    Perform basic health check as per General Adjustments chapter in service manual (available on hifiengine), especially idle/bias.
    Check for any discoloured/charred/heat stressed resistors. Check any fusible resistors, these tend to drift high
     
  3. OMGCat!

    OMGCat! AK Subscriber Subscriber

    Messages:
    3,102
    Location:
    El Sereno, CA
    In higher temps you'll definitely feel more heat as the unit sits idle or while playing but I'd recommend going through the procedures mbz recommends just to give you some concrete ideas on how it's doing.
    Just be sure to be careful when poking around in there. Mini grabbers for your meter leads and only make or break connections while the amp is switched off should have you going through the checks safely.
     
  4. avionic

    avionic " Black Knights " Subscriber

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  5. avionic

    avionic " Black Knights " Subscriber

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    It would be C501 in the power supply . The OEM Rifa needs to be replaced with a new X rated safety capacitor .
     
  6. avionic

    avionic " Black Knights " Subscriber

    Messages:
    42,936
    Location:
    Fort Dodge, Iowa

     

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  7. avionic

    avionic " Black Knights " Subscriber

    Messages:
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    What impedance are your speakers ?
     
  8. 201bk

    201bk New Member

    Messages:
    35
    Location:
    Poland
    both are 8 ohms, I have two pairs.
     
  9. avionic

    avionic " Black Knights " Subscriber

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    At the same time ?
     
  10. avionic

    avionic " Black Knights " Subscriber

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    If so. That's one reason for running hot. 2 pair of 8 Ω in parallel is equal to a 4 Ω load on the amplifiers. That will warm things up a bit.
     
    Last edited: Aug 7, 2018
  11. 201bk

    201bk New Member

    Messages:
    35
    Location:
    Poland
    Well the manual says it's okay to connect two 8 ohm systems, but connecting two 4 ohm systems is not advised.
     

     

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  12. avionic

    avionic " Black Knights " Subscriber

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    Two X 4 Ω would put you at a 2 Ω total load.
     
    Last edited: Aug 7, 2018
  13. avionic

    avionic " Black Knights " Subscriber

    Messages:
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    Regardless... It's going to make your amplifier run twice as hot using two sets of speakers. Especially if you are pushing that volume control up.Can't fool Ohms law.:D
     
    Last edited: Aug 7, 2018
  14. avionic

    avionic " Black Knights " Subscriber

    Messages:
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    Location:
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    I have a similar issue with bridged B-6's running a single set of 8 Ω speakers. In a " bridged " configuration, the amplifiers feel a 4 Ω load. B-6's are not recommended to run with less than 8 Ω load. They will definitely get toasty if I crank up the volume.

    B-6's have the same X- Power supply as the A-960ii as well as power amplifier configuration.

    If you don't get too insane with the volume you will likely be fine. I've been running the B-6's daily for more than a couple years now and they are warm to the touch. My NS-1000M's are like 90db, efficiency. In my small listening space, it doesn't take much to get extremely ( to me ) loud.:biggrin:
     
    Last edited: Aug 7, 2018
  15. avionic

    avionic " Black Knights " Subscriber

    Messages:
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    Yes it is.
     
  16. Dr. Ear

    Dr. Ear Well-Known Member

    Messages:
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    Location:
    Austria
    When connected to a pair of AR-90 (4 Ohms) and listening very loud my A-960 II gets *very* hot.
     

     

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  17. 201bk

    201bk New Member

    Messages:
    35
    Location:
    Poland
    I have Polish loudspeakers and I like them since it's a low cost hi-fi set up, I'm not much of a audiophile and it's the same for me, I'm not keen on high volumes since past the 10 wpc I don't here much of an improvement in bass or anything else. If you don't hear drop past 10 wpc you won't hear it at 100 wpc level too. That's my kind of reasoning. And besides that most of drivers or loudspeakers are measured at 1 wpc and 1 meter so if it gets up to 90 or 94dB at this kind of measurement it gets crazy at 5 to 10 wpc - and during my daily listening I mostly won't get up past 5 wpc at my listening level monitor on my A-960II- LLM measures watts at 8 ohms, so I think when I drive two 8ohms systems I mostly have like 10watts output. And that's fine for me - since I hear stuff as best as I can at this setting and if I can't hear really low bass clearly at this setting it's either the source or speakers or acoustics.

    I guess so since the manual says *NOT* to connect two 4 ohms systems. And that A-960II works best at 8ohms impedance. So this checks out.

    Thanks for the info, avionic. Are these the "foil capacitors" you have to *really* replace in power supply section I've heard so much about? I want as much info as I can since I will get my amp serviced in Warsaw, I think. I've heard so much about this guy in Warsaw, which has mint Elna For Audio and Sanken parts which were used in my Yamaha and measures stuff with professional equipment and sets everything up as the manual says and even replaces the thermal paste on radiators, so I'm thinking about paying up some money and get this stuff done properly since I have to left hands to do this stuff.
     
  18. avionic

    avionic " Black Knights " Subscriber

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    Yes.
     

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