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JDW

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    Anybody used a "Line to Mic Attenuator Cable" on the GH5?

    In: Cameras

    Posted

    5 hours ago, no_connection said:

    Most (from what I have seen) mic input have phantom power, that is why your headphones makes a noise when you plug them into your phone, so plugging a line output into that is not that great. I doubt the mic input have been damaged due to just that as it handles a DC voltage of about 2.3V (think I measured that on my computer) and you kind of run that over the pins while putting it in.

    A few resistors and a couple of caps to remove DC would likely be just fine. if you want to make your own cable. There are plenty of L-pad calculators to get the desired dB of damping.

    I am somewhat relieved to hear that my GH5's Microphone Input is likely not damaged, but I don't have a Mic with 1/8" cable with which to test it.

    The GH5's documentation is seriously lacking details on the Mic Input, but Panasonic sells an optional DMW-XLR1 audio device for the GH5 that provides 48V Phantom power, so I do not believe the built-in Mic Input of the GH5 offers such phantom power output.  (And if you're wondering, I am not interested in buying the $400 DMW-XLR1 because it is bulky and mainly targeting people who want to use XLR Mics, which I do not.)

    I don't see how I can effectively use an L-Pad Calculator because, again, I don't know the LOAD IMPEDANCE (which in this case is the GH5's Mic Input).  Remember, I know the spec only of my D100's Line Output:

    • Output impedance: 220Ω
    • Rated output level: 1.7 V
    • Recommended load impedance: 22kΩ
    • Output level: –21dBm to –15dBm

    The GH5's manual does not give any specifications of the GH5's built-in Microphone Input.  It's probably something low like 680Ω, but that is just a wild guess.  (If it was high like 22kΩ then my D100's Line Output shouldn't clip when fed into that Mic Input.)  So what do you suggest in light of this?

    Furthermore, you mention capacitors to remove DC, but from what I see a lot of L-Pad "Line Level to Mic Level" attenuation cables simply have the dual voltage divider resistors.  I don't see that they have the caps inside.  A previous poster suggest I use a D.I. box, but those are just as big and bulky as the $400 Panasonic DMW-XLR1 box.  If I can solve the problem with a short cable (with needed circuitry built-in) that would be the best overall solution.

    Further thoughts in light of this would be greatly appreciated.

    Thank you.

     

    Anybody used a "Line to Mic Attenuator Cable" on the GH5?

    In: Cameras

    Posted

    Have any of you used a "Line to Mic Attenuator Cable" (passive, resistive padding) with your GH5? My SONY PCM-D100 audio recorder's Line Out is too hot for the GH5's Mic input even when I turn the GH5's audio input gain all the way down. The problem is, I don't know the spec on the GH5's Mic input and I can't find it in the GH5 documentation either. The SONY PCM-D100's Line Out specs are these:
    • Output impedance: 220Ω
    • Rated output level: 1.7 V
    • Recommended load impedance: 22kΩ
    • Output level: –21dBm to –15dBm

    Here is a -50dB attenuator cable on B&H:

    https://www.bhphotovideo.com/c/product/813404-REG/Sescom_LN2MIC_50DB_LN2MIC_50DB_Standard_50dB_Line.html

    Perfect?  Or would a -25dB attenuator be better?  Do any of you have first-hand experience?  Thanks.

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