Running 12v amps via a ac dc converter

Im thinking about building a home audio set up by running my 12v car audio amps by way of a powermax converter. With a normal 120v pre-amp as my control. Thinking of running this set-up to a pair of dynaudio 4ohm speakers.
Or maybe even a set of 8ohm Harbeth's

Has anyone tried this before and can you offer any insight or do's and dont's?

Or is this just a bad idea ?

Thanks for any thoughts on the subject