Tiny Phantom Power Tester

PHANTOM POWER TESTER: An easy and cheap tool for troubleshooting mic lines.

by Scott Helmke

I’ve been making, using, and even giving away these little testers for years now. They cost very little to build (a male XLR and two LEDs, stuff you might even have lying around) and fit right in your toolbag or even your pocket.

How to build

The design is so simple I’m not even going to make a schematic. Each LED just goes from pin 1 to one of the other two pins.  The shorter lead on an LED is the negative lead, and that goes to pin 1.  That’s it!

I’ve gotten pretty good at bending the leads for the closest possible fit, but that’s not too critical either.  Finally, you could put the shell back on and have the LEDs poking out through the cable hole, but I just use hot glue to fill in the space and hold the LEDs in place. 

If you’re used to thinking of always using an LED with a current-limiting resistor, don’t worry.  The phantom power specification calls for two 6.8k resistors in the microphone input, so there’s your resistor.  The effective current is about 14mA, and the voltage doesn’t really matter.  You can use any color LED you like, I had some sporty-looking blue LEDs to play with.  One small caveat is that the LEDs probably will get burned out at some point, due to the extremely simple design, but they are cheap and easy to replace when that happens.

How to use

Plug into a mic input that has phantom power, and the LEDs will light up!  If one of the two signal lines (pins 2 and 3) isn’t connected then only one LED will light.  That’s about it for features, but there are some very useful applications for this.

Just being able to test for the presence of phantom power is useful, such as when a video camera operator needs an audio feed (always at the last minute, of course) from your mixer. Here’s where you don’t want phantom on the line, possibly damaging your mixer output.

My other main use for these testers is onstage troubleshooting.  If a microphone or DI doesn’t work at the line check, what might be the problem?  It could be a bad mic, a bad cable, a bad snake channel, or a bad mic input on the mixer.  Figuring this out quickly is critical, not only in staying on schedule but also helps you look like a real professional. 

How to troubleshoot 

  1. Unplug the source (mic or DI), plug in your tiny phantom tester right on the end of the mic cable.
  2. Turn phantom power on for that input, if it’s not already on.
  3. If both LEDs light, then the mic is bad. Problem solved.
  4. If only one LED lights, then one of the signal lines is bad. If neither LED lights, then the ground line is bad.  Either way, just follow the cable back and keep using your tiny phantom tester.  If both LEDs light at the snake input then the mic cable is bad.  If both LEDs light up at the mixer input then the snake channel is bad.
  5. If you get all the way back to the mixer input with still no LEDs lit up, then either the mixer is bad or there is operator error. Either way you’ve been able to zero in on the problem much faster than before.
  6. If the problem is a missing ground somewhere (no LEDs light up), and you’re really in a hurry, just use a dynamic mic instead. Dynamic mics don’t need the ground connection to work.

The tiny phantom tester is a cheap and effective tool which you should definitely have in your bag.

For more technical tips, sign-up for our email newsletter!

Repairs Highlight

Have a backlog of equipment that needs repair?

If you have overlooked items in need of repair, now may be the time to get ahead of the game. Whether your equipment is in need of repair, evaluation, re-termination, or custom fabrication/modification, we can help support your projects. 

And to help you through the backlog, TC Furlong Inc is reducing it’s repair labor rate by 30% for work scheduled through the end of April.

Repair / Evaluation / Testing – We are an authorized repair center for many of the brands that we use and sell, and routinely work on the full spectrum of professional audio gear.

Re-Termination / Custom Fabrication / Modification – TC Furlong can re-terminate old lavaliers/headset microphones with new connections, or fabricate custom cables and wiring to meet your installation or production needs.

Warranty Support – We can also act as an advocate in any warranty claims you may have.  If you purchased the equipment through TC Furlong, you might also be covered by our Warranty Support Advantage (click here to learn more).

Contact Scott Helmke at 847-367-9588 or shelmke@tcfurlong.com to schedule or discuss your project.

TC Featured on the FILO Podcast

 

TC was recently featured on the FILO podcast with Todd Elliott. Take a listen to hear TC and Todd chat about the barriers to great production: filo.org/episode-041-tc-furlong

TC will still be presenting at the FILO online live-streamed event on May 19 and 20.  

New in Rentals: Meyer Sound ULTRA-X Series

The newest addition to TC Furlong Inc’s considerable loudspeaker inventory is the Meyer Sound ULTRA-X series of compact point-source boxes.

The successor to Meyer’s legendary UPA-1P, the ULTRA-X40 brings the design philosophy of Meyer’s LEO line array family to the form factor of a trapezoidal point source loudspeaker. The X40 and X42 include two 8-inch cone drivers, a 3-inch high frequency compression driver, and a rotatable waveguide. The ULTRA-X40 delivers a coverage pattern of 110° x 50°, while the ULTRA-X42 offers a 70° x 50° pattern for applications requiring a narrower coverage zone.

One of the most noticeable differences between the ULTRA-X series and the UPA is apparent before you run any signal through the speaker; the ULTRA-X40 is 20 pounds lighter than the UPA-1P, weighing in at a little less than 55 pounds. The lighter weight, combined with the integral pole cup and handle, makes this an ideal choice for portable “speakers on sticks” setups. Meyer’s 750-LFC low frequency control element makes for a perfect companion to the ULTRA-X series when portability, power, and exceptional clarity are all required.

The ULTRA-X series is on the cutting edge of point source loudspeaker design. If you’re interested in hearing the difference on your next show, contact our Rental Team at 847-367-9588 or rentals@tcfurlong.com

TC Furlong Inc. is also a longstanding dealer for Meyer Sound, and all other major professional audio manufacturers. To request a purchase quote, get in touch with our sales team at 847-367-9588 or sales@tcfurlong.com

New in Rentals: Cozy Roadie Touring Chair

Newly available in TC Furlong Inc’s extensive rental inventory is the Cozy Roadie Touring Chair package. The Cozy Roadie is an executive-style office chair that easily disassembles and folds down for safe storage and transport in the included SKB Transit Case.

The key to the functionality of the Cozy Roadie is the quick release gas lift, which allows for speedy assembly and disassembly of the chair. The seat back also folds down, making this full-size executive office chair incredibly compact when disassembled. A Cozy Roadie in its Transit Case takes up far less space than a standard office chair, saving valuable truck space.

The molded polymer Transit Case is impact resistant and water tight to protect the Cozy Roadie from wear-and-tear inherent to life on the road, prolonging the life of the chair and saving money over the long haul.

If you’re interested in adding the Cozy Roadie to your next rental, contact the Rental Team at 847-367-9588 or rentals@tcfurlong.com

The Cozy Roadie is also available for purchase from TC Furlong! Contact the Sales Team at 847-367-9588 or sales@tcfurlong.com for a quote on the Cozy Roadie, or products from any of the other manufacturers on our line card.

← Previous Entries

Next Entries →