Is there a Phantom Power "canceller"?

Posted: Thu Apr 03, 2008 2:38 pm

So I'm just a little curious if anyone knows of a device, like a DI or something that acts as a safe guard against Phantom Power? For use with Ribbons basically. I ask because its like a recurring nightmare of mine to just slip on the phantom power button, and then "boom".

Posted: Thu Apr 03, 2008 2:50 pm

Check out the Royer web site. The do's and don'ts section says don't plug in or out when phantom power is on. Other than that, is seems phantom power not an issue. Some of their mics require phantom power, so those can't be damaged by pluggin in with the power on.

Don't know about other brands.

Posted: Thu Apr 03, 2008 9:44 pm

I'm going to go out on a limb and suggest that he already knows the ins and outs.

What he's rightfully fearful of doing is plugging in a ribbon mic into a phantom powered line.

I've got a much cheaper solution -

Masking tape - I only have a few old ribbon mics around and don't use them that often because they're noisy. But I have them all marked with tape that says "PHANTOM ON??????" and before I plug that mic in I check and then double check.
It's worked for me so far, but I'm don't use these out in a classical concert venue.
My .02

Phil

Posted: Thu Apr 03, 2008 9:55 pm

I have a white square of tape on the +48v phantom button on the board with a red circle and line drawn on it. It at least gives pause to think for a moment.

Posted: Fri Apr 04, 2008 1:50 am

I don't know about you guys but I have plugged ribbon microphones in and out of consoles & mixers with Phantom Power On, for over 25 years and have never blown a ribbon microphone yet. I'm talking my own personal RCA 77 DX's and Beyer M160/130's here. So I have a lot to lose if that happens. But old Neve and API stuff didn't have Phantom Power switches. It was either all on or all off. And you didn't/couldn't/wouldn't shut down the console just to plug microphones in or, unplug them. Wasn't done. Didn't do. Wouldn't worry. Didn't bother. We lived through it.

I've lost 2 Shure Beta 58's that had Phantom on the line and weren't being plugged in or out. Go figure? The only microphones I've ever had fail. Just make sure you're using GOOD CABLES! That's where the problems occur.

Phantom Plugger Phucker
Ms. Remy Ann David

Posted: Fri Apr 04, 2008 6:18 am

I know commercial plugs are banned from these forums, but I think this is relevant to the topic. Last year I was commissioned to design a ribbon mic protection/preamp unit. It's currently (rather slowly) going through pre-production trials.

I had to research quite a bit on the possible damage that phantom power can do to all types of microphone, not just ribbon. Not surprisingly, the damaging transients happen at plug-in and/or switch on of phantom power, but can also occur on unplugging, when one signal lead breaks connection before the other. As Remy mentioned, the other main source of problems is faulty cabling. Designing a device that would ensure safety at the microphone connector under all conditions of fault and power cycling while not compromising audio properties was a real challenge. I'll keep you posted.

Posted: Fri Apr 04, 2008 8:07 am

Ditto for everything said so far; I'll just add that I've been under the impression that most phantom power supplies are very low amperage, and won't necesarily blow things up; there's just not enough current to do much damage. STILL, it's always good to keep it out of the circuitry for ribbons, etc., and as everyone has already mentioned, used good cables and be careful patching in and out of stuff.

AEA's TRP has some kind of diode circuitry on the output that blocks phantom power in case it's plugged into something with Phantom. (It's a bit pricey for a device to just block phantom, but it IS a great stereo ribbon mic pre that will never hurt your ribbon mics. )

Posted: Fri Apr 04, 2008 8:08 am

I don't think this would be considered banned in any way. Please keep us posted on all of the details. We really only get pissed when people come around and list an entire post (or 20) with nothing but stuff that they're selling.

If you happen to know of a product that does a specific job and you just happen to be the maker/vendor of that product, there's no harm in mentioning or even heartily recommending it.

Cheers-
Jeremy

Posted: Fri Apr 04, 2008 8:09 am

Of course, back to the OT -

Have you considered the Rode plug? I don't recall the name/model, but it's about $99 and uses a transformer to isolate the mic from phantom all the while boosting the gain and (supposedly) leaving the signal in tact.

Posted: Fri Apr 04, 2008 8:24 am

Most people just use a blocking capacitor to block DC. But a transformer will work.

Posted: Fri Apr 04, 2008 9:57 am

pmolsonmus wrote:

But I have them all marked with tape that says "PHANTOM ON??????" and before I plug that mic in I check and then double check.Phil

Well...hmmm...as long as YOU know, and somebody else doesn't grab them.

Ned Newby.. "I guess he wants to make sure phantom power is on? Confused

"

I'm guessing you make sure it's impossible for that to happen? Wink

Kapt.Krunch

Posted: Fri Apr 04, 2008 11:49 am

I just knew that Boswell was some kind of crazy genius. I just didn't realize he was more sane than the rest of us? Fabulous Boswell! Please keep us posted on your wonderful new circuit. TAA! You British guys are just incredible! When I grow up... I want to be British!

Learning to fake my British accent. Actually I can do Canadian better eh? Nothing you can do a boat that eh.
Ms. Remy Ann David

Posted: Fri Apr 04, 2008 12:17 pm

RemyRAD wrote:

Learning to fake my British accent. Actually I can do Canadian better eh? Nothing you can do a boat that eh.
Ms. Remy Ann David

You need to work on your dialect Remy -

It's "a-boot"

Posted: Fri Apr 04, 2008 12:30 pm

If you need help working on your accent....

Posted: Fri Apr 04, 2008 12:54 pm

wow that girl's pretty cute. i'm a sucker for a southern accent...

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