EOS 70D AC line noise on mic

[Mandi]

This isn't a Canon-specific issue but does affect my video recording setup using my 70D.

I have an external lavalier, wired mic.  On both my phone and my camera I have the same issue:

Running on battery - all good works and sounds great.

Running on AC power - very loud buzz (AC line noise I assume)

Any ideas or reccomendations on how to filter that out?  A setting or a separate device like an in-line filter?

I sure can't be the only one using AC power and a mic.

Thanks!

[Waddizzle]

You have a problem with both your phone and your camera using the microphone.  I suggest that you consult the manufacturer of your lavalier microphone.  It seems that you may not have the proper microphone, or the wiring connections are not being properly executed.

[Mandi]

Not exactly.  Works fine on both using DC power.  Only happens using AC. 

[Waddizzle]

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@Mandi wrote:

Not exactly.  Works fine on both using DC power.  Only happens using AC. 

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My friend, you have a microphone problem.  Contact the microphone manufacturer.  You may not be connecting it properly.  

[Mandi]

Are you not familiar with the common issue of AC line noise interfering with sound systems?  Lucky

[Ray-uk]

Wadizzle is right, this is a microphone problem either relating to a poorly designed mic or a connection problem most likely causing a ground loop. There is a slight chance it could be faulty power supply but this very unlikely.

[kvbarkley]

If the "reverse the AC plug" trick does not work, than the answer is don't use AC, keep to the batteries.

[Mandi]

"reverse the AC plug trick"

 What does that mean?

[kvbarkley]

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@Mandi wrote:

"reverse the AC plug trick"

 What does that mean?

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If your AC plug is not polarized, simply pull it out and reverse it in the socket. Sometimes it matters which end the hot or neutral connect to.

[kvbarkley]

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@Mandi wrote:

Are you not familiar with the common issue of AC line noise interfering with sound systems?  Lucky

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Most of us don't do much video.

Of those that do, most use the internal microphone.

Of those that use external microphones, they keep with battery power.

So, yes, you are one of the very few who use AC power with an external microphone with a DSLR.