Help! SS Amp - 1 channel cuts out after warm up

dee1949
dee1949 Posts: 1,425
edited May 2011 in 2 Channel Audio
....does anybody have an IDEA why? It's a Meridian amplifier. After about 15 minutes the left channel breaks up and dies.
Post edited by dee1949 on
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  • Polkersince85
    Polkersince85 Posts: 2,883
    edited February 2011
    Sounds like a bad solder joint. Unplug it, pop the top and look around.
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  • olilugo
    olilugo Posts: 405
    edited February 2011
    If it happens around a higher note in the sound then it is probably going into protected mode, in this case I will look very closely that the speaker connections are have no strends of coper touching something they should not be touching and that they are very secure and tight.
    Current HT setup
    Mains: B&W 804s
    Center: Polk CSi5
    Surround: Polk FXi3
    Sub: Velodyne DLS-3750R
    Receiver: Pioneer SC-07
    Amplifier: Sunfire TGA5200
    TV: Sony KDS60A2020
    DBP: Sony DBP-S350
    CDP: Pioneer DV-48AV
    Interconnect cables: SignalCable analog II
    speaker cables: SignalCable Ultra Speaker Cables Bi-wire
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  • dee1949
    dee1949 Posts: 1,425
    edited February 2011
    ...thanks guys. Want to to know all the possibilities before I start. Keep them coming. I can't afford another amp like this.
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  • F1nut
    F1nut Posts: 50,566
    edited February 2011
    Bad output device(s).
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • FTGV
    FTGV Posts: 3,649
    edited February 2011
    Did you notice if the left channel was getting hotter than the right before it shuts down?If so it may have a problem with the bias circuit.If by chance the bias current is running too high it would create excessive heat in the output stage that would in turn cause it to go into thermal protection.
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  • dee1949
    dee1949 Posts: 1,425
    edited February 2011
    Thanks guys

    The amp is a Meridian 557. It uses a dual mono design....that probably is why only one channel is effected. I read somewhere that an amp takes about 20 minutes to warm up to full potential. Evidently that is when my problem starts.
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  • sucks2beme
    sucks2beme Posts: 5,601
    edited February 2011
    Given what a nice amp it is, I'd drop it off at the tech!
    But First inspect for the gimme stuff. Look for that small loose strand of wire.
    swap the cables on the back, and see if the problem follows the speaker/wire
    or stays on the same channel. If the same channel, warm it up with nothing on it,
    then shut down, connect the speakers, and then try it.
    "The legitimate powers of government extend to such acts only as are injurious to others. But it does me no injury for my neighbour to say there are twenty gods, or no god. It neither picks my pocket nor breaks my leg." --Thomas Jefferson
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  • dee1949
    dee1949 Posts: 1,425
    edited February 2011
    ...ok - on future test...the amp does not go out....it breaks up in certain frequencies. Played on 8 ohm speakers for an hour...no problem. Hooked to my Maggies and after awhile the left channel broke up.
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  • megasat16
    megasat16 Posts: 3,521
    edited February 2011
    From what you said, there are a few possibilities and you don't really know till you open up the amp and trace the signal and check the parts such as relay.

    It's time to take the amp to the Pro for checkup and repair.
    Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone. :redface::biggrin:
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  • soundfreak1
    soundfreak1 Posts: 3,414
    edited March 2011
    Sounds like output relays to me
    Main Rig:
    Krell KAV 250a biamped to mid/highs
    Parasound HCA1500A biamped to lows
    Nakamichi EC100 Active xover
    MIT exp 1 ic's
    Perreaux SA33 class A preamp
    AQ kingcobra ic's
    OPPO 83 CDP
    Lehmann audio black cube SE phono pre, Audioquest phono wire (ITA1/1)
    Denon DP-1200 TT. AToc9ML MC cart.
    Monster HTS 3600 power conditioner
    ADS L1590/2 Biamped
    MIT exps2 speaker cable
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  • soundfreak1
    soundfreak1 Posts: 3,414
    edited March 2011
    Had simular prob. Once sounds like output relays.
    Main Rig:
    Krell KAV 250a biamped to mid/highs
    Parasound HCA1500A biamped to lows
    Nakamichi EC100 Active xover
    MIT exp 1 ic's
    Perreaux SA33 class A preamp
    AQ kingcobra ic's
    OPPO 83 CDP
    Lehmann audio black cube SE phono pre, Audioquest phono wire (ITA1/1)
    Denon DP-1200 TT. AToc9ML MC cart.
    Monster HTS 3600 power conditioner
    ADS L1590/2 Biamped
    MIT exps2 speaker cable
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  • HB27
    HB27 Posts: 1,518
    edited March 2011
    dee1949 wrote: »
    ...ok - on future test...the amp does not go out....it breaks up in certain frequencies. Played on 8 ohm speakers for an hour...no problem. Hooked to my Maggies and after awhile the left channel broke up.

    Have you tried switching the speaker wires from one speaker to the other and see if it follows the speaker or channel?
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  • kappclark
    kappclark Posts: 136
    edited April 2011
    soundfreak1 wrote: »
    Sounds like output relays to me

    The amp I took in for service last year had same plm (right ch fading, then cutting out .. totally randomly) ... bad speaker relay..it was replaced, and no plm.....

    (BUT NOW, IT HAS JUST STARTED DOING IT AGAIN..!!)
    *************************
    ** Bill Clark Windham, VT **
    *************************
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  • reeltrouble1
    reeltrouble1 Posts: 9,312
    edited April 2011
    Tubes Rule!!! oh, and they sound better.

    RT1
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  • kappclark
    kappclark Posts: 136
    edited April 2011
    My "solution" to the dropout/reduced volume is to turn up the volume, then the signals get balanced..

    I don't want to send it to the shop, so I continue to utilize this ghetto workaround...the monitor 60's don't mind..
    *************************
    ** Bill Clark Windham, VT **
    *************************
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  • greyhnd
    greyhnd Posts: 17
    edited April 2011
    Possibly nothing more than dirty controls or maybe a protection relay. You might try a good cleaning with DeoxIT or another of the available contact cleaners. It's an inexpensive first step.
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  • kappclark
    kappclark Posts: 136
    edited May 2011
    soundfreak1 wrote: »
    Sounds like output relays to me

    I bit the bullet, and took the lid off the Parasound...pretty easy to spot the relay ..removed it from its protective shell..(it was mounted "upside down" )

    Used a matchbook cover to clean the contacts ..no deoxit or cleaner..4 strokes

    Fantastic change...total balance between both ch, and a stable image..I was glued to the sound .. hadn't sounded this good since I had the relay installed 2 years ago..guess I bought some serious time before I convince myself that there is a better amp

    Thank you to all who made repair suggestions in this thread and others...
    *************************
    ** Bill Clark Windham, VT **
    *************************
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