Once you understand why the preview output on the Panasonic MX50 works that way, it makes sense. Unfortunately it doesn’t make it any more useful for live video!! …
I have seen various complaints on the web from people claiming that their MX50 video mixer is broken. They go something like this: “The preview output is broken. It only ever shows the SAME as the main program output, rather than showing what is selected on the NON-live buss, like most other video mixers”
Well, unfortunately this is exactly what it was designed to do. You have to understand that the MX50 was designed for doing linear tape editing, not for doing live video. It’s recent adoption to that function is really an afterthought. In linear tape editing, it is important to be able to reherse the transition that you are going to do next, while you are still recording something, and that is why the MX50 allows you to select one buss (A or B) to be played out the program outputs regardless of what is happening on the T-bar, while the preview output shows what WOULD happen to the main output as a result of the T-bar actions. To control this, you need to use the ‘Program’ section at the top right of the mixer. Normally this would be set to ‘Effect’, which is kind of like an ARM button for the T-bar. If instead you select ‘A’ or ‘B’ then that plays whatever is selected on that buss directly to the program output.
So think about the 3 buttons as
A = play out A buss all the time (and enable the T-bar on the preview output) B = play out B buss all the time (and enable the T-bar on the preview output) Effect = arm the T-bar to fade between busses.
Unfortunately there is no way that I know about to tell the MX50 to automatically switch between these modes, to allow you to view the non-live buss on the preview output.
The BEST workaround to this is to have preview monitors for every input on the MX50, so you don’t really need a single preview output after all. These can just be mono monitors or old TVs or whatever – quality is not important, but of course you need to be able to route the signal in and back out of them to go to the MX50 inputs.
One option is to buy set of four or three mono monitors in a rack unit. This is what we have and it works well.