Alternative Power for Mic Receiver Box at DVinfo.net

Lisa Bennett · September 19th, 2008, 11:24 AM

I have a lav mic system that is not made for camera mounting. It has the standard lav and belt clip transmitter. The receiver is one I have connected to the camera using the mic output connector which is then feed into an xlr adapter which is then cabled into the HD100U Input 2. This mic system requires sregular electrical power, not battery operated. It's more of a wireless mic system that would be used by a person that is connected to a regular sound system.

I would like to know if there is a way to connect the receiver box to some type of diy battery pack that won't cause interference so that I won't have to plug-in to electricty when at a shoot. I could tether the receiver box to the tripod along with it's alternative power. The receiver's current power requirement is 9v, 300 mA AC/DC adapter

Any suggestions?

Thank you
Lisa

Shaun Roemich · September 19th, 2008, 12:09 PM

A quick web search led me to this comparison of high current draw on 9v batteries.

Discharge tests of 9 volt transistor radio batteries

Your 300mA draw LOOKS like it could be facilitated by literally taking a 9v battery clip with bare ends and soldering it to an adaptor the right size and configuration to fit into your wireless receiver.

The numbers that the batteries on the chart give leads me to believe the battery life under a 100 - 500 mA draw will give you between 200 and 450 mAh. SO after doing the math, depending on how much your receiver ACTUALLY draws (the listed 300mA supply will be overkill), you should get 1 hour to 4 hours, based on actual battery used (different batteries handle high current draw differently - see the chart) and ACTUAL receiver draw.

Could someone with a better understand of electronics make sure I have this right.

Steve House · September 19th, 2008, 12:24 PM

Quote:

Originally Posted by Lisa Bennett

I have a lav mic system that is not made for camera mounting. It has the standard lav and belt clip transmitter. The receiver is one I have connected to the camera using the mic output connector which is then feed into an xlr adapter which is then cabled into the HD100U Input 2. This mic system requires sregular electrical power, not battery operated. It's more of a wireless mic system that would be used by a person that is connected to a regular sound system.

I would like to know if there is a way to connect the receiver box to some type of diy battery pack that won't cause interference so that I won't have to plug-in to electricty when at a shoot. I could tether the receiver box to the tripod along with it's alternative power. The receiver's current power requirement is 9v, 300 mA AC/DC adapter

Any suggestions?

Thank you
Lisa

Carefully check the power specs for the receiver in its manual to verify whether it needs 9 volts DC or 9 volts AC. Most of the time it would be DC, true, but not always. One way to tell is to see if there is a wiriing diagram for the power connector that shows which pin is positive and which is negative. If the receiver expects its power supply to send it DC then a suitable battery could be used. But if the adapter is sending low voltage AC then substituting with a battery wouldn't work.

If it's a common brand like a Senn G2, if it came down to it you could buy just the portable receiver to use with the transmitter you already have.

Lisa Bennett · September 19th, 2008, 12:36 PM

The one I currently have isn't anything fancy. I have a VERY basic plain ole lav mic from Radio Shack that I used for an interview (model 32-1257). Believe it or not it worked pretty good. It had some noise which I was able to adjust in post. I got to thinking about how to maybe use a different way to power it for when no electricity is available so decided to post.

I looked at the receiver specs in the paperwork and it has it as "power requirement 9V, 300 mA AC/DC Adapter.

This is a temporary mic for now but if anyone has ideas on alternative power, I'd like to hear it.

Thanks for the replies.
Lisa

Lisa Bennett · September 19th, 2008, 04:26 PM

Also, know of any camera mounted wireless sales going on any place right now? I'm not looking to buy the best one out there this week but would like to get another one. I'm considering buying a camera mounted one for some upcoming interview work I need to do.

Is the Audio Technica Pro 88W good for use with JVC GY-HD100U?

Thanks,
Lisa

Steve House · September 19th, 2008, 05:11 PM

Quote:

Originally Posted by Lisa Bennett

Also, know of any camera mounted wireless sales going on any place right now? I'm not looking to buy the best one out there this week but would like to get another one. I'm considering buying a camera mounted one for some upcoming interview work I need to do.

Is the Audio Technica Pro 88W good for use with JVC GY-HD100U?

Thanks,
Lisa

Be careful who you buy from and what you buy if you find something on sale. A few weeks ago the FCC announced that not only are sales of wireless units operating in the 700mHz band (692mHz - 804mHz I think it is) going to be illegal after Feb 2009, the operation of existing units currently in the field will also be illegal anywhere in that band. While you probably be able to get away with it for a while without running afoul of the law yourself, due to the low power of wireless rigs, there will be a lot of activity in that band as newly licensed high-power users move into that part of the spectrum and it will become increaingly difficult to find a clear part of the band in which to operate without interference. Reputable pro audio dealers are fully aware of the situation and will be completely up-front with you about it but who knows how concerned the local music store, big-box outlet sales-droid, or eBay seller will be about your ability to use next year the wireless unit he wants to sell you today. Caveat emptor.

Steve Oakley · September 20th, 2008, 03:06 PM

go to a local batteries plus store or equivalant and have them make you a custom battery pak. You ll want 7 cells which will give you about 10.5v charged maybe closer to11v. Shouldn't hurt anything to be a lilltle hot. Should cost well under $50 for C cells. Thereal question is do you have a charger that can charge it? I have a Pag charger that can handle whatever you plug in to it. If you don't the economical way might be to get a used hardwire ecm44 on eBay for $150 if you don't have to be wireless.

That or get a senn g2

September 19th, 2008, 11:24 AM	#1
Lisa Bennett Major Player Join Date: Apr 2006 Location: Central, FL Posts: 397	Alternative Power for Mic Receiver Box I have a lav mic system that is not made for camera mounting. It has the standard lav and belt clip transmitter. The receiver is one I have connected to the camera using the mic output connector which is then feed into an xlr adapter which is then cabled into the HD100U Input 2. This mic system requires sregular electrical power, not battery operated. It's more of a wireless mic system that would be used by a person that is connected to a regular sound system. I would like to know if there is a way to connect the receiver box to some type of diy battery pack that won't cause interference so that I won't have to plug-in to electricty when at a shoot. I could tether the receiver box to the tripod along with it's alternative power. The receiver's current power requirement is 9v, 300 mA AC/DC adapter Any suggestions? Thank you Lisa Last edited by Lisa Bennett; September 19th, 2008 at 11:56 AM.

September 19th, 2008, 12:09 PM	#2
Shaun Roemich Inner Circle Join Date: Sep 2002 Location: Vancouver, British Columbia (formerly Winnipeg, Manitoba) Canada Posts: 4,088	Caveat Emptor - Buyer Beware A quick web search led me to this comparison of high current draw on 9v batteries. Discharge tests of 9 volt transistor radio batteries Your 300mA draw LOOKS like it could be facilitated by literally taking a 9v battery clip with bare ends and soldering it to an adaptor the right size and configuration to fit into your wireless receiver. The numbers that the batteries on the chart give leads me to believe the battery life under a 100 - 500 mA draw will give you between 200 and 450 mAh. SO after doing the math, depending on how much your receiver ACTUALLY draws (the listed 300mA supply will be overkill), you should get 1 hour to 4 hours, based on actual battery used (different batteries handle high current draw differently - see the chart) and ACTUAL receiver draw. Could someone with a better understand of electronics make sure I have this right. __________________ Shaun C. Roemich Road Dog Media - Vancouver, BC - Videographer - Webcaster www.roaddogmedia.ca Blog: http://roaddogmedia.wordpress.com/

September 19th, 2008, 12:36 PM	#4
Lisa Bennett Major Player Join Date: Apr 2006 Location: Central, FL Posts: 397	The one I currently have isn't anything fancy. I have a VERY basic plain ole lav mic from Radio Shack that I used for an interview (model 32-1257). Believe it or not it worked pretty good. It had some noise which I was able to adjust in post. I got to thinking about how to maybe use a different way to power it for when no electricity is available so decided to post. I looked at the receiver specs in the paperwork and it has it as "power requirement 9V, 300 mA AC/DC Adapter. This is a temporary mic for now but if anyone has ideas on alternative power, I'd like to hear it. Thanks for the replies. Lisa __________________ Lisa http://www.victoryNOWfilmsandtv.com

September 19th, 2008, 04:26 PM	#5
Lisa Bennett Major Player Join Date: Apr 2006 Location: Central, FL Posts: 397	also...camera mounted wireless Also, know of any camera mounted wireless sales going on any place right now? I'm not looking to buy the best one out there this week but would like to get another one. I'm considering buying a camera mounted one for some upcoming interview work I need to do. Is the Audio Technica Pro 88W good for use with JVC GY-HD100U? Thanks, Lisa __________________ Lisa http://www.victoryNOWfilmsandtv.com

September 20th, 2008, 03:06 PM	#7
Steve Oakley Trustee Join Date: Apr 2006 Location: United States Posts: 1,158	go to a local batteries plus store or equivalant and have them make you a custom battery pak. You ll want 7 cells which will give you about 10.5v charged maybe closer to11v. Shouldn't hurt anything to be a lilltle hot. Should cost well under $50 for C cells. Thereal question is do you have a charger that can charge it? I have a Pag charger that can handle whatever you plug in to it. If you don't the economical way might be to get a used hardwire ecm44 on eBay for $150 if you don't have to be wireless. That or get a senn g2