[Update 12/5: I was able to do some testing this past weekend (ATR-3350 and VideoMic) and am quite pleased with the results. Check back soon for a new blog posting with some example clips. I definitely need to work on the cabling to make it easier to move around, though...]
I have been lusting after a real video camera with manual controls and external mic input for a long while now. Last week, I was finally able to get a Canon M41 and two extra high capacity batteries. I effectively paid more by getting them from Best Buy because I used credit card point, but the total cash outlay for all that was $4. Nothing to complain about…
Anyway, the camera has an internal 32GB of flash and I added two 16GB flash cards to it. It should have more than enough capacity for anything we plan to do with it.
One drawback of the ATR-3350 is that it has a mono 3.5mm plug on the end of it. When you plug it into the M41, only the left channel has audio. I wanted to be able to use one or two mics and not make a bunch of custom cables, so I built a little box. Here is the schematic:
I didn’t actually use jacks on the camera side since I was not able to find much in the way of short shielded 3.5mm patch cables on eBay or at Amazon. I had some cut shielded cables with 3.5mm plugs on one end laying around, so I used two of those instead of J1 and J6. I built a little box (photos below) and wired the jacks up point to point. The outer barrel of the jacks are threaded, so they’re mounted on the box sides with nuts.
The headphone splitter is self explanatory. It does not offer independent volume control and it is less than efficient because two sets of headphones is half (in the general case) the impedance, but it should be sufficient for most of our purposes. I could have bought a splitter, but I had jacks lying around. The length a splitter would stick out of the camera and the leverage it could produce is eliminated by building it into the box.
The mic side is where the real action is…
Any mic plugged into J2 (Stereo/Left) delivers audio to camera left channel. If the mic is a stereo (or a two channel mono like the VideoMic), right channel audio will be delivered to the camera if nothing is plugged into J3 (Right).
When a mic is plugged into J3, the camera right channel gets the audio because the switch in the jack disconnects the J2 right channel. If a stereo mic is plugged into J3, its left channel is delivered to the right channel on the camera.
A secondary reason for building this box is to minimize the insertions into the camera’s jacks and to mechanically protect them when the short patch cables I incorporated into the box are plugged in. The box greatly reduces the possibility of mechanical stress on the camera’s jacks.
If one got really ambitious, this “device” could be made on a small PCB with PC mountable jacks. I was not so ambitious because I only needed to make one, but if there is sufficient interest, I’d consider generating a PCB and making a kit for those without the ability to build this on their own. If you’re interested, send me an email (david AT SundaysChildSnapshots DOT com) with “Mono Mic Combiner” in the subject. If there is sufficient interest, I will consider drawing up a board and making kits. Initial napkin calculations seem to indicate a selling price of about $18-20 each.