recordinghacks



phantom power kills ribbon microphones, truth vs. fiction

Wednesday, April 2nd, 2008 | by


Show me a guy with a ribbon mic, and I’ll show you a guy who’s afraid of phantom power.

The two go hand-in-hand, as if the mere presence of phantom power could cook all the ribbons in the studio, whether they’re wired or not. But that sounds less like phantom power than like ghosts in the machine.

I’m here to tell you that the idea that phantom power is a ribbon killer is mostly a myth. Pervasive, yes, and grown from a seed of truth, yes, but blown way out of proportion — according to no less an authority than the very folks who make ribbon mics.

Of course, the myth is in some ways propagated by these same vendors, which doesn’t help matters. Case in point: AEA’s “Ribbon Pre” was designed with “83db of clean gain and no dangerous phantom power.” Little wonder there are guys on the message boards making comments about dedicating a mic pre to their new ribbons and putting a piece of tape over the +48v button.

Here’s what Royer Labs has to say about phantom power and ribbon microphones:

Royer ribbon microphones are not usually affected by the presence of phantom power… Turning the phantom power on or off after the mic is connected should pose no problem whatsoever.

So if Royer Labs, makers of market leading ribbons like the R-121 and SF-12, says phantom power won’t hurt its microphones, then what’s cooking all those ribbons? Myths, unlike the egos of most guitar players, require at least occasional affirmation to grow.

In a word: your patchbay.

What?! says the typical home-studio owner. I don’t have a patchbay!

Exactly. So peel the tape off that +48 button and stop sweating the phantom-power myth.

We’re assuming your cables are in good shape. If any of them shorts pin 1 to pins 2 or 3, whether due to a bad cable or a bad connector, you will indeed cook that ribbon if you apply phantom power. But why you’d use a junky old short-circuited cable with your nice ribbon mic is beyond us, so forgive us for sounding preachy.

The problem with patch bays is that they use TRS (tip-ring-sleeve) connector cables, which can (during insertion) momentarily apply phantom power, if present in the patchbay circuit, to the parts of the TRS connector where they should not.

Read more in the Royer Labs whitepaper, or better yet, check out Jon Ulrigg’s video demonstration. Jon is the proprietor of ShinyBox, maker of highly-regarded, hand-built ribbon mics. In this video, Jon bares the ribbon from one of his mics and demonstrates the complete lack of disaster that follows when phantom power is applied. He demonstrates the shorted-cable scenario too, allowing us to see the ribbon excursion that’s just about equivalent to the time I put my M380 too close to the kick head and blew the moving coil off its track.

Phantom power effect on ribbons (hint: not much)

Update, 2008-12-01: Ribbon mic expert Mark “Marik” Fouxman wrote in with a cautionary postscript about some vintage ribbons:

Marik

There are some vintage ribbon microphones that have transformer secondary with grounded center tap. For those, phantom power is a NO NO.

Marik doesn’t recommend that vintage ribbon mic owners open up the mic housings to check for the wiring on the transformer. Rather, if you own a vintage ribbon and you have a question about its ability to survive patchbay wiring with phantom power, have the mic’s internals checked out by an expert before making assumptions you might regret.

Tags: , , ,
Posted in Microphones, Video | 1 Comment »




One Response to “phantom power kills ribbon microphones, truth vs. fiction”

  1. Bob Crowley

    February 19th, 2009 at 4:39 pm

    The companies you mention don’t want to do any more ribbon repairs than necessary. Phantom power can be applied in a way that will stretch many ribbons without a patchbay – all you need are XLR pins of unequal length when connecting, or disconnecting them.

    The fear of P power is real, and even if it is only an occasional failure mode, it does happen and it will destroy an aluminum ribbon. The example that Jon puts up shows that EVENLY applied P power is fairly OK. It’s too bad that there are many times that is not the case.

    Bob

Leave a comment