3.5mm to XLR mic cable at DVinfo.net

Colin McDonald · July 9th, 2008, 03:15 PM

Just thought I'd share this - maybe it should have been in the Audio forum.

When making up a cable to connect a Rode NTG-2 mono mic to an HV30, I thought I would see what happened if I just connected the cable as signal (Tip & Ring shorted) to pin 2 and ground to pin 3. It worked fine until I touched (or put my hand near) the NTG-2 when a high pitched whine became audible through the monitoring headphones. This whine was constant even when several hundred yards away from any source of electrical interference. It disappeared when I shorted pin 1 to pin 3, which is the way I would normally have wired the cable anyway.

The difference in audio quality using the external mic over the built in mic is very noticable even with this simple cable (I don't have a Beachtec and was hoping not to have to buy one).

C.S. Michael · July 13th, 2008, 09:16 PM

just FYI, you can connect an XLR mic without a Beachtek. Just use an XLR to mini cable. I bought an AT8341 for less than $20.

Colin McDonald · July 21st, 2008, 02:45 PM

Quote:

Originally Posted by C.S. Michael

just FYI, you can connect an XLR mic without a Beachtek. Just use an XLR to mini cable. I bought an AT8341 for less than $20.

Maybe I'm missing something here, but I thought I had described how I'd done just that, going in to detail of how I wired up the cable.

Scott Gold · November 7th, 2009, 12:52 PM

Hey Colin,
I'm thinking of making a XLR to 3.5mm adapter for my NTG2 and 5DmkII.
I'm very familiar with solder/electronics.....I'm just wondering if it's as straight forward as buying the components and soldering them together?
What schematic did you use? Did it require capacitors or resistors?
Details would be greatly appreciated!
Thanks!

Colin McDonald · November 8th, 2009, 02:03 PM

I'd forgotten about that post.

I just use a stereo minijack cable which I chopped one end off and soldered on an XLR plug instead. No resistors or capacitors needed. As the cable is unbalanced, I kept it as short as possible. That's the tradeoff - unbalancing the connection makes it more prone to interference, even though the actual cables used are coaxial. To keep the connection balanced right up to the camera makes the set up much more complicated, with a transformer or Beachtec type device needed as close to the camera as possible.

With the short cable length and a good strong audio source I haven't been troubled by interference so far.

I did the bridging inside the XLR because being a bigger connector, I find the XLR is easier to work with, but it is possible to bridge the tip and ring connections inside the minijack instead.

Here's a schematic:

July 9th, 2008, 03:15 PM	#1
Colin McDonald Major Player Join Date: Dec 2007 Location: Glasgow Scotland Posts: 674	3.5mm to XLR mic cable Just thought I'd share this - maybe it should have been in the Audio forum. When making up a cable to connect a Rode NTG-2 mono mic to an HV30, I thought I would see what happened if I just connected the cable as signal (Tip & Ring shorted) to pin 2 and ground to pin 3. It worked fine until I touched (or put my hand near) the NTG-2 when a high pitched whine became audible through the monitoring headphones. This whine was constant even when several hundred yards away from any source of electrical interference. It disappeared when I shorted pin 1 to pin 3, which is the way I would normally have wired the cable anyway. The difference in audio quality using the external mic over the built in mic is very noticable even with this simple cable (I don't have a Beachtec and was hoping not to have to buy one).

July 13th, 2008, 09:16 PM	#2
C.S. Michael Regular Crew Join Date: Oct 2006 Location: Birmingham, AL Posts: 135	just FYI, you can connect an XLR mic without a Beachtek. Just use an XLR to mini cable. I bought an AT8341 for less than $20. __________________ Bored? Check out my blog (shot with Sony EX1, Canon HV20, Letus Mini, Sony HC3, Nikon D40): LongLongHoneymoon.com

November 7th, 2009, 12:52 PM	#4
Scott Gold Regular Crew Join Date: Jul 2003 Location: Irvine, CA Posts: 163	Hey Colin, I'm thinking of making a XLR to 3.5mm adapter for my NTG2 and 5DmkII. I'm very familiar with solder/electronics.....I'm just wondering if it's as straight forward as buying the components and soldering them together? What schematic did you use? Did it require capacitors or resistors? Details would be greatly appreciated! Thanks! __________________ www.venture-multimedia.com

November 8th, 2009, 02:03 PM	#5
Colin McDonald Major Player Join Date: Dec 2007 Location: Glasgow Scotland Posts: 674	I'd forgotten about that post. I just use a stereo minijack cable which I chopped one end off and soldered on an XLR plug instead. No resistors or capacitors needed. As the cable is unbalanced, I kept it as short as possible. That's the tradeoff - unbalancing the connection makes it more prone to interference, even though the actual cables used are coaxial. To keep the connection balanced right up to the camera makes the set up much more complicated, with a transformer or Beachtec type device needed as close to the camera as possible. With the short cable length and a good strong audio source I haven't been troubled by interference so far. I did the bridging inside the XLR because being a bigger connector, I find the XLR is easier to work with, but it is possible to bridge the tip and ring connections inside the minijack instead. Here's a schematic: Attached Thumbnails Last edited by Colin McDonald; November 8th, 2009 at 02:09 PM. Reason: The curse of copy/paste - wrong label on XLR pin 3

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