Ian Thomson Posted February 26, 2009 Report Share Posted February 26, 2009 I've been told by a microphone distributor here in Australia that unplugging 48v phantom powered microphones before switching the phantom supply off; can cause damage to the microphone. Whilst it would obviously be ideal to shut off the ph/power switch every time, in practice - it can be tough to get to the power switch in time, and boomers will 'accidentally' how-swap their cable. how much damage will this do? do you shut down a channel (turn off it's ph power) before unplugging? or just "fader-down"? any solutions that people have found? (external switches/boxes etc) Ian I'm not concerned with the audible "thump" when a mic is hot-plugged (that's unavoidable), but quite curious about the damage occurring to a mic capsule. Quote Link to comment Share on other sites More sharing options...
Scott Clements, CAS Posted February 26, 2009 Report Share Posted February 26, 2009 I use Sennheiser MKH50, 60... my boom man plugs and unplugs into his phantom power supply all day without turning it off. He does it at a bunch of times a day. So far the mics don't seem to mind a bit. That's not to say it's a good idea, it's just an observation. Perhaps the day will soon come where I see the results of thousands of plugs/unplugs into that phantom power supply... scott Quote Link to comment Share on other sites More sharing options...
André Boisvert Posted February 26, 2009 Report Share Posted February 26, 2009 http://groups.google.com/group/rec.arts.movies.production.sound/browse_thread/thread/be79b4fcce25f245?hl=en&q= Quote Link to comment Share on other sites More sharing options...
Noah Timan Posted February 26, 2009 Report Share Posted February 26, 2009 I've been told by a microphone distributor here in Australia that unplugging 48v phantom powered microphones before switching the phantom supply off; can cause damage to the microphone. It's an old wives' tale. I wouldn't worry about it. I've never seen (or even heard of) any actual documented damage done to a microphone from this. My boom ops have plugged and unplugged dozens of times a day for many years without any perceptible damage to the mics, and I know plenty of other mixers whose operators have done the same without incident. Quote Link to comment Share on other sites More sharing options...
Jeff Wexler Posted February 26, 2009 Report Share Posted February 26, 2009 It's an old wives' tale. I wouldn't worry about it. I've never seen (or even heard of) any actual documented damage done to a microphone from this. I agree that there is little to no chance of ANY damage to a phantom powered microphone when unplugging it while phantom power is still active. I would like to point out one thing, which does relate to phantom power and potential damage, relates to Schoeps microphones (this may apply to other microphones that have the colette feature of interchangeable capsules). You must never remove the capsule from the body of the mic, like to change to another capsule, insert the CUT-1, etc., while the microphone is still powered up. Always disconnect the microphone before changing the capsule. At the very least, while not technically damage, the removal of the capsule with phantom power applied has been known to cause arcing and deformation of the crucial contact between the capsule and the amp... so, don't do it! - Jeff Wexler Quote Link to comment Share on other sites More sharing options...
old school Posted February 26, 2009 Report Share Posted February 26, 2009 Mine would all be dead if this was true, but that is just my experience, I could be wrong. I know you can kill a ribbon mic by feeding it 48v power, not that most of us use these for production work. CrewC Quote Link to comment Share on other sites More sharing options...
soundtrane Posted February 26, 2009 Report Share Posted February 26, 2009 If at all, care should be taken during plugging and unplugging - to protect the ears of the people wearing headphones during this activity... -vin Quote Link to comment Share on other sites More sharing options...
Glen Trew Posted February 26, 2009 Report Share Posted February 26, 2009 I've plugged and unplugged for decades without any problems. No harm to dynamic mics (moving coil) either. You even get use to the pop after 15 or 20 years. gt Quote Link to comment Share on other sites More sharing options...
Philip Perkins Posted February 26, 2009 Report Share Posted February 26, 2009 I've done the Schoeps de-+re-head thing w/o disconnecting in the heat of battle--it sounded ugly but it worked. I've sent p48 to my Beyer ribbons by mistake (one time for a whole evening) and they still are fine. Not a good idea with a vintage RCA ribbon though.... Philip Perkins Quote Link to comment Share on other sites More sharing options...
old school Posted February 26, 2009 Report Share Posted February 26, 2009 My two Royers ribbons as well as my Nadys say no 48v power. Jim Webb who has a hell of a collection of mics of all kinds and times was the one who told me that first. I have zero first hand experience trying them with 48v power, but I don't think I want to try that. CrewC Quote Link to comment Share on other sites More sharing options...
Don Coufal Posted February 27, 2009 Report Share Posted February 27, 2009 I've really never heard of this being a problem and I think all of us have done this for years. I have heard however that you should not remove the capsule on a microphone like the schoeps with the microphone plugged in and receiving voltage. This can damage the mic. However before we were informed of this we had done that very thing many times. Now I always unplug the mic before changing a capsule. Better safe then sorry. Quote Link to comment Share on other sites More sharing options...
Scott Smith Posted February 27, 2009 Report Share Posted February 27, 2009 Actually, this depends on the design of the ribbon. If it employs a transformer, and is there is no grounded center tap, then phantom power won't hurt it. (Due to the fact that there should be no difference in the DC potential across the two signal leads). However, if one of the signal leads accidentally gets grounded, things get a bit ugly... What should always be avoided is plugging a ribbon or dynamic mike into a T-Power input, which does have a 12 volt potential between the two signal leads. Not something that most transformers like to see on the secondary winding.... --Scott Mine would all be dead if this was true, but that is just my experience, I could be wrong. I know you can kill a ribbon mic by feeding it 48v power, not that most of us use these for production work. CrewC Quote Link to comment Share on other sites More sharing options...
Ian Thomson Posted February 28, 2009 Author Report Share Posted February 28, 2009 Thanks for all the replies. Ian Quote Link to comment Share on other sites More sharing options...
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