I've been researching on the topic of audio monitoring in the Canon 5D Mark II and I thought that the most inexpensive solution would be to get a 3.5mm minijack female to a RCA female stereo cable in order to use the RCA cable provided with the 5D and connect headphones to it to monitor the sound.
Something like this;
However, I didn't know that once the AV minijack is plugged in the 5D the camera display gets disabled because the camera "thinks" that I am connected an external monitor, which I don't have.
A black camera display turns the 5D in a pretty useless thing for video... Moreover, I can't even hear anything from my headphones..
Is there a way to enable the camera display even with the AV minijack connected to the camera?
Barring that, perhaps looking at getting the Tascam DR60 under camera recorder might be the next cheapest alternative? They are now under $200 for the slightly older model, and also record on the fly at two different levels. That would allow you to monitor and record three different tracks. I've been pretty happy with mine. There is even a newer model with four XLR inputs!