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Why don't I get a signal plugging a lav directly into my Zoom?

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Noam Osband
Why don't I get a signal plugging a lav directly into my Zoom?
on Nov 21, 2017 at 7:22:05 pm

I have these lavs that I use with my wireless kit. The mics have a 1/8' pin, and I want to connect it directly to my Zoom H6 recorder. I bought a converter that goes female pin to male XLR, but when I plugged it in, it wasn't getting any signal. I feel like this is a very easy, obvious issue but I don't know what the problem is! Anyone here know what I'm doing wrong?


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Bruce Watson
Re: Why don't I get a signal plugging a lav directly into my Zoom?
on Nov 21, 2017 at 9:27:35 pm

Probably because you aren't powering it correctly. Lavs in general take "plug-in power". If you plugged your mic into an XLR with full phantom power, you may have fried your lav. To get a signal, you'll probably need a phantom to plug-in power converter.

As an example, on the Oscar Soundtech lav page, about half way down and first item after the "Accessories" heading, is a picture of their Power Supply-XLR converter that they sell to convert phantom power to plug-in power for their lav mics.


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Noam Osband
Re: Why don't I get a signal plugging a lav directly into my Zoom?
on Nov 22, 2017 at 5:38:40 am

Bruce, cool beans. I'll look into that product. In the meantime, for my own knowledge, what do you mean when you say they take "plug-in power"? That sounds to me like phantom power but obviously it's not that.

Thanks!


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Richard Crowley
Re: Why don't I get a signal plugging a lav directly into my Zoom?
on Nov 22, 2017 at 12:32:06 pm
Last Edited By Richard Crowley on Nov 22, 2017 at 12:35:45 pm

"Plug-in power" is typically a low voltage (3-5V) which is applied to an unbalanced connection directly to a typical electret capacitor microphone capsule. This is the kind of microphone used in lav mics, headset mics, computer mics, cell phones, etc. etc. etc.

"Phantom power" is typically a high voltage (48V) applied to both internal wires of a balanced pair. It is converted for use internally in (typically) a condenser microphone.

Because of the balanced vs. unbalanced nature of typical 3.5mm connections vs. typical XLR connections, and particularly because of the very significant difference between the 5V vs. 48V power they are in no manner compatible or interconnectable. That is why various adapters are necessary such as mentioned by Mr. Watson.

Suggest testing your microphone to confirm that it still works with your wireless transmitter. You may have actually destroyed the microphone depending on exactly how your (unidentified) adapter was wired.

Ref: https://en.wikipedia.org/wiki/Phantom_power#Other_microphone_powering_techn...

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Recording audio without metering and monitoring is exactly like framing and focusing without looking at the viewfinder.


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Eric Toline
Re: Why don't I get a signal plugging a lav directly into my Zoom?
on Nov 22, 2017 at 1:42:08 pm

This will do the power conversion for you but you'll need to get it with a 3.5mm TRS input connector.

https://www.trewaudio.com/product/remote-audio-lavpssp/




$49.99 - ‎In stock

"I push the RECORD button and hope for the best"


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Bruce Watson
Re: Why don't I get a signal plugging a lav directly into my Zoom?
on Nov 22, 2017 at 4:44:11 pm

[Noam Osband] "In the meantime, for my own knowledge, what do you mean when you say they take "plug-in power"? That sounds to me like phantom power but obviously it's not that."

Phantom power is not plug-in power at all. Two completely different things.

Wikipedia gives a reasonable definition of phantom power. On that page, fairly far down, you'll find a paragraph on plug-in power:

"Plug-in-power (PiP), is the low-current 3 V to 5 V supply provided at the microphone jack of some consumer equipment, such as portable recorders and computer sound cards. It is also defined in IEC 61938.[13] It is unlike phantom power since it is an unbalanced interface with a low voltage (around +5 volts) connected to the signal conductor with return through the sleeve; the DC power is in common with the audio signal from the microphone. A Capacitor is used to block the DC from subsequent audio frequency circuits. It is often used for powering electret microphones, which will not function without power. It is suitable only for powering microphones specifically designed for use with this type of power supply. Damage may result if these microphones are connected to true (48 V) phantom power through a 3.5 mm to XLR adapter that connects the XLR shield to the 3.5 mm sleeve.[14] Plug-in-power is covered by Japanese standard CP-1203A:2007[15] A similar line-powering scheme is found in computer sound cards. Both plug-in-power and soundcard power are defined in the second edition of IEC 61938.[16]"

IOW, just what Mr. Crowley said. Note the part where it talks about how damage may result if you attach a mic that needs plug-in power to a true phantom power source.


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Bruce Watson
Re: Why don't I get a signal plugging a lav directly into my Zoom?
on Nov 22, 2017 at 7:11:03 pm

Interestingly, it looks like Rode just recently released a product that might do what you want. Clearly, YMMV. It's the Rode VXLR+ which converts the signal *and* converts power from phantom to plug-in.

Maybe Mr. Crowley has seen one of these things and can tell us more. The Rode website will only show me the VXLR, not the + so I'm not entirely sure of the specs.


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Noam Osband
Re: Why don't I get a signal plugging a lav directly into my Zoom?
on Nov 22, 2017 at 7:40:21 pm

How do I know if this will work with my lavs? I have OscarTech lavs; thankfully, the one I used wasn't fried.

Their power to pin converters are 75 each. I mentioned the RODE VXLR+ to them and they thought it wouldnt work. They also have a financial incentive to tell me that. Is there a way to gauge the specs before buying? I don't entirely trust OscarTech as they just keep pushing me to buy their own one (which, as it is a business, as well they should).


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Bruce Watson
Re: Why don't I get a signal plugging a lav directly into my Zoom?
on Nov 22, 2017 at 9:37:51 pm

[Noam Osband] "How do I know if this will work with my lavs?"

Excellent question. Lacking specifications on either the lavs or the rode interface, I have no way to answer.

[Noam Osband] "I don't entirely trust OscarTech as they just keep pushing me to buy their own one (which, as it is a business, as well they should)."

Yeah, well. I don't suppose you'll trust me too much either when I tell you that I'm running two of the OST lavs, with two of the OST phantom to plug-in interfaces. The combination sounds exceptionally good to my ears. And I know the OST parts work together well; I've been using them for years.

The only problem I have with the OST XLR interface is the lack of any kind of a clip (like the Rode's belt clip) to physically hold it in place. I'd rather not have to be constantly improvising, although I'm getting to be pretty good with velcro and of course gaffer tape. ;-)


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Noam Osband
Re: Why don't I get a signal plugging a lav directly into my Zoom?
on Dec 4, 2017 at 7:00:07 pm

I appreciate the feedback Bruce. I feel a bit stuck here since it'll take a while to figure out if a different product would work with my OST mics, so I'll probably pay their price. It's just a lot more than other products out there on the market, and I have no sense if it's worth the extra money.


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