Sorry, I don't have an A50 for you, but I can tell you that the transformer-based DMP-50 mic preamps are really worth having! This is especially true with some cap and opamp upgrades. I have a couple of them mounted in an external box, and use them in my studio often. For a bottom of the line console, they really came with some great mic pre's.
If anyone has some worn-out A50 consoles (the switches didn't hold-up very well), please, pull the mic preamp boards out of them before they go to the dumpster. I'm not sure where the mic transformers came from, but they are worth the effort.