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).

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.

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.

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!

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: