using large box dvd/cd/player as base for small tube amp

I need to consolidate units to save space. I have a Pioneer Elite for cd's, it is a large box. I want to put my
Sophie Baby on the top back area. I was going to use a piece of plywood the size of the cd player and then
the amp. Is this a reasonable idea or could it create a problem?
thanks for any ideas.
Merry