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Author Topic: How to wire TRS mini (from lavalier) to XLR P48 (into mixer)?  (Read 10059 times)

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Offline sdroakton

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QUESTION:
How do I build a microphone cable adapter with a 3.5mm TRS female jack on one end and an XLR male plug on the other, so that I can connect my Countryman EMW lavalier mic directly to my field mixer without going through a wireless transmitter/receiver?

IS THIS RIGHT? 
How about if I build a short cable with a 3.5mm TRS female jack on one end and a XLR male plug on the other end, wired as such:
   - TRS Tip to XLR Pin 2
   - TRS Ring to XLR Pin 3
   - TRS Shield to XLR Pin 1

WHAT PUZZLES ME:
- Is the wiring proposal above correct for a balanced 48V connection that will work with this specific lav mic?  Will it blow anything out - the lav or the mixer?
- Countryman sells the EMW lav hardwired for XLR, but they say it has a preamp inside.  If the wiring proposal above is correct, why is a preamp necessary?  (So it can run without P48?)

BACKGROUND:
- I have  a Countryman EMW lavalier microphone wired with a 3.5mm TRS male connector as Tip = Red (pos),    Ring = Black (neg), Sleeve = Shield.
- The Countryman EMW lav requires power.  The rep at Countryman Associates (I called them) says the EMW lavalier can take 48V phantom power.
- My SignVideo ENG-44 mixer provides 48V phantom power to an XLR female jack. 
- I want to build this, not buy it (unless it's super cheap)

EXTRA CREDIT
I also have a Countryman B3 lavalier mic with a TS mono connector (wired Tip=Red, Sleeve=Black+Shield).  How should a cable adaper be wired so that I can power this lav directly from my mixer with 48V phantom power?
« Last Edit: March 13, 2010, 07:49:13 PM by sdroakton »

Offline ghellquist

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Re: How to wire TRS mini (from lavalier) to XLR P48 (into mixer)?
« Reply #1 on: March 14, 2010, 08:53:13 AM »
For the EMW it seems more or less correct. Connect the sleeve to pin 1 XLR. Then balanced signal goes to 2 and 3 in the XLR. These might come from pin and sleeve from the TRS, but the TRS could have been configured for some specific wireless so check inside it to see that all three leads are connected.

It sounds like a bit of confusion, the EMW does not have a full preamp inside. It has some electronics, yes, that you might mislable as a preamp. I believe a better term is headamp instead. You will still need to amplify the signal further. One purpose of the preamp is to give the mic the power it needs. This could be done with a few components and a battery if you preferr that to P48.

It is basically impossible to destroy a 48V phantom input on a mixer by shorting or other connections of the three pins within each other, so no need to worry there. 48V may destroy a mic like the B3, the EWM was designed to take it.

If you want to connect the B3 to 48V power you will need more stuff in between. It will take a few resistors and a condensator as minimum. Do check the circuits in a neighbouring thread here dealing with the 4061.

// Gunnar

Offline sdroakton

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Re: How to wire TRS mini (from lavalier) to XLR P48 (into mixer)?
« Reply #2 on: March 14, 2010, 02:46:51 PM »
Thanks Gunnar - very helpful.

If any others have insights to share, please do.

-Scott

Offline sdroakton

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Re: How to wire TRS mini (from lavalier) to XLR P48 (into mixer)?
« Reply #3 on: May 21, 2010, 04:55:47 PM »
In case anyone's curious, I did try the above wiring and it doesn't work.  Anyone new ideas out there?

Offline Erick del Valle

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  • what about this pair of stealthy mics?
Re: How to wire TRS mini (from lavalier) to XLR P48 (into mixer)?
« Reply #4 on: August 16, 2010, 01:57:07 AM »
A lavalier works with plug in power (1-9V) 48V could burn it, A phantom power adapter makes the trick,  I'm not familiar with countryman by the way, check this:

http://naiant.com/naiant/inlinedevices.html

http://naiant.com/pfaspecification.html

Erick del Valle
Santiago de Chile
Erick del Valle
Santiago de Chile

Offline live2496

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Re: How to wire TRS mini (from lavalier) to XLR P48 (into mixer)?
« Reply #5 on: August 16, 2010, 04:55:24 PM »
For the DPA 4060/4061 the DAD6001 basically does the same thing. I measured the voltage at the adapter and it is 9v. The mixer supplies a 48v source. There are electronics in that adapter that steps down the voltage.
AEA R88MKII > SPL Crimson 3 > Tascam DA-3000

Offline Erick del Valle

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Re: How to wire TRS mini (from lavalier) to XLR P48 (into mixer)?
« Reply #6 on: August 16, 2010, 05:57:04 PM »
the datashet for that particular lavalier says:

Power Requirements :
Phantom: 6 to 50 Volts
Wireless: 1.5 to 24 Volts

We can therefore conclude that the XLR has involved electronic inside.


Hope helps

Erick del Valle
Santiago de Chile

Erick del Valle
Santiago de Chile

Offline sdroakton

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Re: How to wire TRS mini (from lavalier) to XLR P48 (into mixer)?
« Reply #7 on: August 20, 2010, 09:15:22 PM »
Thanks guys

 

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