I am looking for a amplifier to drive a passive subwoofer . I see the
popular option is to use Parts Express plate amps. What do people do with
these amps when they are not part of the subwoofer enclosure? Do they just
let their plate amps sit exposed on their equipment racks or do they build
an enclosure for it?

In lieu of that, I was thinking about getting something like a used Adcom
GFA-555 and run it mono for the sub. Does anyone have any suggestions for
other amps that would be suitable for this application?

Thanks,
Greg