C100: Lav mic XLR adapter - noise issues - Help please!

U

Uchujin

New member
Wondering if anyone can help:

I have an audio technica lav mic that has a 2.5mm stereo jack plug.
I'd like to run it into ch1 XLR input on my C100 so I can run a rode video mic into ch2 XLR.

I bought a stereo 2.5mm to XLR converter plug and rewired the connections inside so left and right from the lav go to pin 2 of the XLR converter (pin 1 - ground, pin 3 - nothing) so that it is now a stereo mini jack to mono XLR.
In theory this should work but whilst I'm getting a good level in camera I'm also getting quite a lot of background noise particularly a rhythmic beating noise.

Is this some problem with the ground when going from the lav to the XLR?

Any suggestions of how to do this?

Need to film some interviews next week and was hoping not to have to go dual sound but straight to the C100.

Thanks in advance.
 
I looked at those.
Problem is Rode video mic and my Audio technica lav both have stereo mini jacks.
Would that connector work with a stereo mini jack input?
 
I have a couple of these. What model audio technica lav do you have because I have a few of them too and I will try it out for you and let you know.
B
 
Thanks Brian.
Actually having done some more research I think you are right and thats the one I need.
Unfortunately, I live in Tokyo and today (sunday) and tomorrow are holidays so the only shops I can find that have them are closed and I need the adapter early Tuesday morning :(
Think I may have figured out the correct way to wire the one I have. Now if I can just find a soldering iron........
 
You've created a very nice antenna and you're possibly picking up all of your local taxi firms.

Your C100 XLR socket is looking for a balanced input - pin 1 earth/shield, pin 2 hot (+) and pin 3 cold (-). It's the shield around the cable going to pin 1 that is designed to pick up the noise and then an op amp in the runs it out of phase with the signal, effectively cancelling out any unwanted noise.

You've bought a professional camera and spent a premium on something that gives you balanced mic inputs with the bonus of phantom power. You really don't need to spend a fortune on a mic with a balanced output - messing around with 2.5mm jacks will get you into a World Of Pain.

Ben.
 
Ben thank you for your reply.

I understand how an XLR plug works and the correct wiring of a balanced input.
I thought seeing as the cable from the rode mic was so short there would not be an issue with radio interference.
I thought it may be an issue with the long cable on the lav but was hoping it might be ok.
These converter plugs are widely available so my impression was that it would be an acceptable solution.

I have only very recently got the C100 and was shooting on a 5D before where I was happy with the audio from the lav and rode mic into an external recorder.
Of course a mic with a balanced output would be better for the C100.

I was just looking for a quick solution to this issue with the equipment I had to hand as time was an issue.
 
I have Senneheiser wireless lav system.
They come with a cable like this: http://www.bhphotovideo.com/c/produ...nology_XVM_101M_XVM_101M_Angled_3_5mm_to.html

Its 3.5mm for the wireless receiver, and the other end is XLR which I put in CH1 into my C100, then use Rode VideoMic into the Mic Input directly on the cam for CH2.

Although mine is maybe 12 inches long which is perfect, take a look through for a cable (i much prefer cables vs adaptors)
 
@Chappeldigital.
Thank you!
I didn't realise you could use the xlr socket on the handle for CH1 and the cam mic input for CH2 (Doh!)
I had tried before with the input set to "EXT" for CH2 but got no sound.
Switching it to internal ( counter intuitive, no?) and plugging in the lav to the mic socket works perfectly!

Now have Rode to xlr on CH1 and lav to CH2 into the mic input with no noticeable background noise!

Thanks this will work perfectly for what I need.
 
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