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Thread: Soundcraftsmen MA5002

  1. #16
    Senior Member Ed Zeppeli's Avatar
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    I am currently running an MA5002 to power a pair of 2234s in my set-up.

    The amp does a great job of powering them but makes an audible hiss (white noise). The noise is gain related on the amplifier itself. At about 50% gain the noise virtually disappears but where I run them the noise is present; not incredibly loud, just 'there'.

    I'm wondering if any of the more tech oriented folks here can recommend some troubleshooting tips for me. Is this just the nature of the beast? Would a dose of deoxit at the inputs and gain pots possibly help or is this just due to age and and will it likely require a trip to a good tech to fix?


    Thanks much,

    Warren
    DIY Array, 2242 sub, 4408, 4208, Control 8SR, E120 Guitar cab, Control 1, LSR305.

  2. #17
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    Do you get the noise with out any inputs connected to the amp?

  3. #18
    Senior Member BMWCCA's Avatar
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    Quote Originally Posted by Mike Caldwell View Post
    Do you get the noise with out any inputs connected to the amp?
    ". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers

  4. #19
    Senior Member Ed Zeppeli's Avatar
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    Quote Originally Posted by Mike Caldwell View Post
    Do you get the noise with out any inputs connected to the amp?
    No, I'll give that a shot. I can mute the inputs easily enough. I know, not the same thing.

    One other clue. I'm using TRS connectors to the MA5002 wired from an XLR balanced output in the usual balanced configuration. Would that possibly offer an explanation?

    Cheers,

    Warren
    DIY Array, 2242 sub, 4408, 4208, Control 8SR, E120 Guitar cab, Control 1, LSR305.

  5. #20
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    Quote Originally Posted by Ed Zeppeli View Post
    No, I'll give that a shot. I can mute the inputs easily enough. I know, not the same thing.

    One other clue. I'm using TRS connectors to the MA5002 wired from an XLR balanced output in the usual balanced configuration. Would that possibly offer an explanation?

    Cheers,

    Warren
    Try it with the amp completely disconnected from any input source.

    What type of unit is the input source, a balanced connection from your input source's output to the amp's input is the best way to do it.

  6. #21
    Senior Member Ed Zeppeli's Avatar
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    It's the balanced out of the dbx Venu360. I'll try some things and report back.
    DIY Array, 2242 sub, 4408, 4208, Control 8SR, E120 Guitar cab, Control 1, LSR305.

  7. #22
    Senior Member Ed Zeppeli's Avatar
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    Update

    No inputs; no hiss. Instead, without any inputs connected I get a mild (60 hz?) hum which doesn't seem present with inputs attached. It's quiet so it's possible that the white noise masks it but I doubt it.

    Sooooo, does this narrow things down a bit?


    Thanks,

    Warren
    DIY Array, 2242 sub, 4408, 4208, Control 8SR, E120 Guitar cab, Control 1, LSR305.

  8. #23
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    Quote Originally Posted by Ed Zeppeli View Post
    No inputs; no hiss. Instead, without any inputs connected I get a mild (60 hz?) hum which doesn't seem present with inputs attached. It's quiet so it's possible that the white noise masks it but I doubt it.

    Sooooo, does this narrow things down a bit?


    Thanks,

    Warren
    That helps narrow it down.
    Now try it with the 360 connected to the amp but with nothing connected to the inputs on the 360 and see what you get.

    The 60hz hum may be nulled out when the amp is connected to balanced input, having said that there should be no 60hz or harmonic there of from an power amp that has nothing connected to the inputs.

    In the utility setup menu on the 360 there is an input and out gain/level set up menu, adjust those levels may help your noise issue if it's a gain structure issue.
    If the system is quite with the 360 connected to the amp and with nothing connected to the 360's inputs that means your noise is coming from the source unit connected to the 360's inputs.


    Let me know
    Mike C.

  9. #24
    Senior Member Ed Zeppeli's Avatar
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    Ok. I'm on it as soon as possible....


    ...and thanks for the walk-thru.


    DIY Array, 2242 sub, 4408, 4208, Control 8SR, E120 Guitar cab, Control 1, LSR305.

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