There's an echo in here.
Ribbon mics, all of them, have transformers. Dynamic mics may or may not, but in either case, what's sitting between pin 2 and 3 is a coil of wire. If you attach Pin 2 to 48V and pin 3 is floating, nothing happens!

Basic electronics. For work to be done (work=damage in this case) voltage must be applied across the mic so that current can flow. If you don't attache pin 3 to anything, you only have voltage, no current. And, Power (work done) = Voltage X Current. Take away either voltage or current, and you have zero power, no work done, no damage.

Now, to be very clear, there is exactly one condition where P48 can damage a mic: either pin 2 or pin 3 must be tied to pin1, or grounded at the shell. That places P48 across the mic, current flows, work (damage) is done. Otherwise, P48, by design, cannot damage a mic.
Plug in that XLR any old way you want, P48 on or off, you can't hurt a ribbon mic, unless somewhere in the cable or mic, Pin 2 or 3 is connected to ground, in which case, current will flow. But also, without P48, you'd have an unbalanced mic line, guaranteed to be noisy. So fix that.

Yeah, try plugging in a Coles ribbon mic with the phantom on.

I have two Coles microphones that were destroyed by phantom power.

Curious, was it a transformerless Pre?

Let me take a wild guess: 4038, and both were destroyed by swapping the mic at the mic connector, that fabulous weird connector that requires an adapter cable to get to XLR-M? And the weird connector, as stated in the literature, is wired 1-high, 2-low, 3-shield. And somebody miss-wired the adapter cable.

The only other possibility is that Coles grounds a transformer center tap, but I sold my Coles so I can't check.

This happened quite a while ago.
I was in a studio in Long Island, NY.

They had a Trident console in their CRM at the time.

All, I know is that the console phantom power was always on and they 4038s popped when the associate engineer plugged them in.

They were indeed Coles 4038s, and those adapter cables were wired to MXLR correctly.

All, I know is that the console phantom power on that Trident desk that was in the studio we were working in was always on.

I personally heard my coles 4038s pop when the associate engineer plugged them in at the mic panel.

OK, wonder if they had Mic Pre patching?
IF they did you CAN send 48V across pin 2 & 3 via the TT connector....

True, but he said, "pop when the associate engineer plugged them in at the mic panel", which implies the patch was already in place, and it popped when plugged in. A TT connector would have to be pretty badly inserted, like half hanging out, to short 1 to 3.

Anyway, there's a cause, and it isn't just that P48 was on and an XLR was plugged in. That simply won't do it. There had to be something else wrong, or the mic's transformer had a grounded center tap. Unlikely, but Coles does some pretty unlikely stuff.

And Trident may have been doing transformerless preamps at that point ( though the original Series 80 was a transformer input with two TLO-71 as gain stages. Really! And they called that "clean". ), and a failure mode would be one input leg of a transfromerless input stage at or near ground potential. But, we don't have specifics and troubleshooting is hard enough long-distance without being long-time too.

Either way, I'm not doubting your mics were blown, and P48 was present, but just plugging in an XLR won't do that without something else being wrong somewhere.

Interesting. I tried to mate XLRs at an angle and make one pin connect before the others on purpose. I couldn't do it.

There’s at least one company (Rode ?) which designed and mfrd the inner contact sleeve of pin 1 in their female xlr’s to be longer than the other two (ie closer to the outer edge of the connector face)….so that pin would always be the first to make contact connection before the other 2.

Edit: maybe it was a connector mfr rather than a mic mfr…or else pin 1 on the mic base was slightly longer ?…anyway, same goal/intention.

Makes sense in the same way that the ground pin in a wall socket is supposed to prevent a short in the event that you stick a plug halfway in and then inadvertently drop your butter knife in the gap. Assuming, of course, that your wall socket is installed with the ground pin on top, which they never are because they're so much more appealing when they have a smiley-face.

Consider using the most expensive microphone you can find, and keep trying.

What does the cost of the microphone have to do with the ability to insert an XLR such that the pins don't contact at the same time?

And...

I already explained with basic electronics why, without there being some other error in the system, connecting Pin 2 before Pin 3 with P48 applied will have no negative effect.

Consider it considered. :-)

Experiences…

I was setting up mics in a the studio, standing next to a 4038, when I heard a strange “snap”. It was the Cole’s ribbon popping. A brilliant 2nd at the Neve console’s TT bay hot-patched that connection.

On location with direct mic lines, all known-to-be working XLR cables. An RCA77 was deployed for something and sounded fantastic during morning rehearse/record. During a break some cables had to be undone to move a piano into place. All cables were reconnected accurately but the 2nd turned that 77’s preamp +PH on by accident. It did not pop but Its level was down and freq response was mangled. The ribbon had been stretched and unusable. Very disappointing for the session. Later the mic repair tech reported a bad solder joint as the cause of the voltage differential. Can’t vouch for the veracity.

Another time on a stage with known good cables and mics. Sound check a-ok. Just before show a stage hand closes a sliding fire door on a mic cable. That channel had a ribbon mic which erroneously carried PH and blew the ribbon.

Yes, it’s rare but it happens. But phantom is just as likely to damage preamps as well as ribbons. Most preamps I have studied do not have adequate protection. You won’t notice each minuscule insult, but over time the damage accumulates. I have been able to plot increased THD, IMD and reduction of CMRR from accumulated hits. Insidious! (Pueblo has taken such casualties into account and have designed our preamps with immunity)

Besides possible gear damage, from a fidelity concern, running delicate mic signals in the presence of phantom is not optimal. No circuit is perfect. There are always some finite imbalances and parasiticals . Do such things ever enhance fidelity? Of course not. They can only degrade quality by some finite amount.

So what am I recommending? Do Nothing! By that I mean expose non-phantom devices to nothing. How hard is it to do nothing? Nothing harms nothing and it’s free of charge.

He was making a joke.

I lost a brand new M160 to phantom once.

Shinybox posted a video long ago showing a naked ribbon and the faults that would stretch or snap it, worth finding.

there's noting wrong with anecdotal evidence...

...but for every quote citing the desastrous effects of applying phantom power to a ribbon mic (and specifically the m160 and m260), i could mention an equal amount of situatios in which this did exactly NOT happen and no noticeable damage was being done!

and believe me, it happend more than once in a period of close to 40 years and several thousands of live gigs/festivals/broadcasts.



[depending on how the ribbon is hung, it seems to me that the likelihood of damage from improper storage is greater - without wanting to start a new discussion but then, i'm no tech or designer and i'll gladly admit that this is also just an anecdotal note, based on the observation of microphones that were very likely never exposed to phantom power*, but should have been brought back to life after decades of sleeping beauty in a closet of a now defunct radio studio, but failed to do so.


* why i have good reasons for this assumption is outside the scope of this thread.]


p.s. i do disengage phantom power on all channels when storing scenes in my digital desks (if i have to bother about this at all: more often and for good reasons, the monitor tech is in charge of that, assuming were talking about standard situations in which mics go into passive 3-way splitter) and use cloudlifters on my beyer's - the latter mainly to have more equal gain settings accross the desk though in case i'm using a festival patch with varying mics (which is quite often the case as it's so damn fast - and speed of use is king when live mixing)...

If I'm the one doing it, I always disable phantom before plugging/unplugging because I think its safer for the preamp, never mind the mic. When I'm performing, I have no attention to spare on whatever the sound tech is doing. Mostly, I'm just trying not to get my instrument bashed on a crowded stage. That's exactly how it was Monday night: There was no time to plug in my live rig, even though I had it sitting in the wings. I walked onstage with my instrument and my M160 mounted to a low gooseneck stand and tossed the cable end over the edge of the stage. Someone plugged it in, we spent 15 seconds getting monitor levels and we were on with the show.

David

Don't the blocking capacitors typically take the hit when phantom is applied...I thought that was the rationale behind the 'slow phantom power ramp-up' (or more simply, the 3-5 sec output muting) employed in some mic preamps and audio interfaces ?

This thread has parallels to the whole evolving Covid/mask thing. We thought P48 was harmless, so maybe it's not, so we'll be more careful and shut it off. Fine.

I'm thinking it wouldn't be that hard to attach a phantom blocking barrel to my stand with a short XLR cable so it's always there and I don't need to worry about it. Too bad the commercial ones cost $50 for something that's basically a pair of capacitors. Maybe I'll build one.

Could you possibly post a schematic sketch here Rick….that would be a handy safety accessory worth making at home on a rainy afternoon !

i have a related question, dont want to start up a new threat i think thats best


so im not clear on how to plug in and unplug my ribbon mic.
also im not clear if gain clipping will hurt the mic.

so lets say i record a shaker, then i turn the preamp gain up so high that the mic gain clips.
is that bad in any way ?


and when im done, should i first unplug the cable, then turn off the preamp power (not phantom power obv but the regular preamp power)
cause if i turn that off while the ribbon is plugged in, i definitely get a spike that clips the gain

any advice would be appreciated

Gordon does that. Mutes the device for 30 seconds when turning phantom power ON/OFF.

Deedeeyeah gave the correct answer 2 years ago. Unfortunately no one that posted with vagueness has never bought an M160 and tead the documentation (attached) or bothered to even d/l it. The documentation is 2 pages long. The figure on the second page shows the transformer in the microphone.

Sincerely, thank you for stating the obvious to the readers Deedeeyeah.

I have 160s and 260s. We try to not have p48 on on their channels when we configure the board for the job, but in the heat of a last minute sound check or mic-choice-chang-of-heart they've been swapped into lines where the p48 was on. The pop wasn't pleasant but the mics survived and sound just fine. So don't do p48 with them if you can but don't shoot yourself if you slip up on a gig and it happens.

Would such a device degrade the signal in any way?

Normally, they're just a pair of series capacitors in series with pins 2 and 3, so no problem if you buy nice ones. You could alternatively use an inline transformer; those do change the sound a bit. The third option is an inline booster, but I haven't found one I like the sound of. If I know I'll be dealing with a long snake run, I just bring my AEA preamp.

The reason I'm asking is because devices such as the one you recently acquired engage/disengage phantom power at the software level, and one unfortunate bug can cause an expensive accident involving one's say AEA R44C. Dedicated preamps with actual physical phantom power switch are obviously preferable when it comes to using expensive ribbon mics. But one may not want to invest in a dedicated preamp or they may like the preamps in their AX Center. That's why I was wondering if a phantom blocking barrel permanently connected to say an AEA R44C would be a potential solution, but more importantly at what expense signal quality-wise.