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Thread: Demeter Mighty Minnie TGA-1-180D

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    Demeter Mighty Minnie TGA-1-180D

    My tech partner and I have been trying to get to the bottom of a speaker jack issue, wondering if anyone here had any helpful advice.
    Whenever the speaker jack is touched with our bare hands, the sound cuts out with a small clicking sound. It doesn’t cut out when touched with tools.
    Now, whenever we took the speaker jacks out of the chassis and let them float freely, the sound doesn’t cut out if touched with anything at all.
    My partner thinks that it’s parasitic oscillation or a capacitance issue, not a grounding issue. Nothing seems to be touching or shorting the wires or jacks inside the chassis.

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    is it a bridged output amp?
    in that case the load is not grounded,you have 2 amp outputs connected to the jack,i guess if you ground it somehow a protection cuts out the whole thing.

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    Supporting Member Jazz P Bass's Avatar
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    The output section is of the Class D type.

    Why are you touching the jack?

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    Tech pardner chiming in.

    It has the ICEPOWER module. The output goes into protection/shutdown when the SHIELD of the speaker cable plug is touched. This happens with speaker jacks IN AND OUT of the chassis.

    You can hear the amp cycling if you leave your finger on it.

    Yes we can tell the customer to stop reaching back there on gigs and fingering his plug while he's playing the solo to Beat It... but is there any mod or fix for this?

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    Supporting Member Jazz P Bass's Avatar
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    If the amp is configured in bridge mode, that may explain the oddity.

    The speaker shield is then half of the output.

    If so, the amp is detecting a 'short'.

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    Don't forget the joker g1's Avatar
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    Quote Originally Posted by lowell View Post
    This happens with speaker jacks IN AND OUT of the chassis.
    In the first post, he said it did not happen if the jacks were floating from the chassis?

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    Quote Originally Posted by The Dude View Post
    But, I did learn something. There are protons, neutrons, electrons, ............ and morons.

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    He misspoke

    Happens in and out of chassis

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    Don't forget the joker g1's Avatar
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    Thanks. Then I won't recommend insulating washers.

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    Quote Originally Posted by The Dude View Post
    But, I did learn something. There are protons, neutrons, electrons, ............ and morons.

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    Yup thanks.. they're plastic jacks anyways

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    Supporting Member The Dude's Avatar
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    Quote Originally Posted by Jazz P Bass View Post
    If the amp is configured in bridge mode, that may explain the oddity.

    The speaker shield is then half of the output.

    If so, the amp is detecting a 'short'.
    ^^^^^^ That. If they are running the amp in bridge mode, neither speaker + or - is ground and neither will like being grounded.

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    “Yeah, well, you know, that’s just, like, your opinion, man.”

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