View Full Version : Connecting an XLR-terminated lav to a Sennheiser G2 wireless kit


Craig Irving
December 13th, 2007, 08:26 AM
Hi everyone, I know this is probably a basic question and presumably an obvious answer, but my ECM77B terminates in an XLR connection, yet the Sennheiser G2 kit I'm using requires a mini-jack connection obviously.

I figure all I need is an XLR --> Minijack cable to go into the transmitter, but going through the forums here I've been concerned about impedence matching, etc. etc.

Is it better to just use the supplied lavs that come with the Sennheiser G2? Obviously they're not going to be as good, but I suppose it's easier than having the subject walk around with the DC-78 power supply in his pocket, and a transmitter on him, and a big XLR --> Minijack cable.

The subject will be giving a lecture, so that's a lot of junk to walk around with.

Any advice?

Bill Ravens
December 13th, 2007, 08:43 AM
B&H has a 3.5mm minijack to dual XLR(left and right) adapter.

Steve House
December 13th, 2007, 08:52 AM
Is your mic hardwired to the power supply or is there a connector? You mentioned the DC-78 power supply but isn't that to supply power to mics equipped with the 4-pin mini connector?

Craig Irving
December 13th, 2007, 09:23 AM
Sorry guys. You're absolutely right. I read over the brochure too quickly. There's no model number for the power supply it's just integrated. I made a mistake in assuming the model number for it was the DC-78, but that appears to be a completely different accessory.

This one is a regular 3-pin XLR connection (XLR-3-12C type connector).

My best guess is that I'll need this:
http://www.bhphotovideo.com/c/product/158477-REG/Hosa_XVM105_Stereo_Mini_Angled_Male.html

Bill Ravens
December 13th, 2007, 09:49 AM
yes, that's the right one. Sennheiser usually provies one with the G2.

Craig Irving
December 13th, 2007, 09:56 AM
I believe they provide a male XLR to go back from the receiver into the camera (which I'll also be using).

Greg Bellotte
December 13th, 2007, 12:21 PM
i think you'll find that the XLR to mini cable in that link might not work very well. the sennheiser transmitter input has bias voltage to power the plug in lavs. some models (500 series) even have three conductor input jacks and operate as mic or line depending how you wire it. in any case, your sony ecm has the power module at the end of the lav wire, right? using a regular XLR to mini cable, the bias voltage may interfere with the audio only signal that comes out of the sony XLR. (on the other hand-it might work. feel free to try it won't hurt anything)

the correct mic input cable from sennheiser is the CM-1.

http://www.bhphotovideo.com/c/product/310613-REG/Sennheiser_CM1_XLR_Female_Microphone_Cable.html

it is pretty pricey for what it is. if you are handy with soldering irons, you can build one pretty cheap. the key is to use a small capacitor to block the bias voltage from getting to your microphone. this arrangement works very well.

other options include getting lavs that are already wired for use on the G2 transmitter. in this case the mic is terminated in a mini-plug and the capsule powers from the transmitter bias voltage. no extra junk to carry. :-)

Bill Ravens
December 13th, 2007, 12:57 PM
oops! you're right Greg. Page 43 of my Senn EW100 manual shows the following xmit connector assignments:
Tip +
Ring NC/Gnd
Sleeve -

Craig Irving
December 13th, 2007, 01:09 PM
Hmmm that's too bad. Cause I'm only borrowing the G2. I would hate to have to buy a cable that is only specific for the Sennheiser in case I buy different wireless kit down the road. Maybe I should just use the lavs that come with the Sennheiser for times that I absolutely need wireless.

Jeffery Magat
December 13th, 2007, 01:37 PM
Hmmm that's too bad. Cause I'm only borrowing the G2. I would hate to have to buy a cable that is only specific for the Sennheiser in case I buy different wireless kit down the road. Maybe I should just use the lavs that come with the Sennheiser for times that I absolutely need wireless.

That, or just go to Trew Audio and rent. :P

Craig Irving
December 13th, 2007, 01:46 PM
Good idea. I'll give them a call. For some reason I didn't figure they would rent out a specialty cable like that.

Hsien Yong
December 13th, 2007, 08:04 PM
Hi Craig,
I would recommend using the lavs supplied with the Sennheiser G2 kit. You don't have to get a special cable and it's alot lighter for the subject to walk around with.