stacking DAC on Monster power conditioner

It goes without saying that the best option is to avoid stacking when/if possible. If you must stack, the component which does not require passive cooling through vents in its top cover would be the one to place on the bottom. It's component suicide to place a component that does require passive cooling via it's top vents beneath another component, where the separation is only a few inches. Also, the footing plays a role. A piece of gear much larger than another piece usually means the larger piece need to go on the bottom.  From a sound quality perspective, it would probably be best to isolate your DAC, although you may be hard pressed to hear any negative effect. So in answer to your question, its not necessarily "bad", just less than ideal. 

@ thank you for the affirmation... The Brooklyn has vents on the top and bottom....I'll look into some kind of isolation feet for a little more air....