Can audio components run too cool?
This is an interesting question. We've all experienced how different our systems sound when we first turn them on. Cold they sound like their temperature: stiff, sluggish, perhaps a bit sterile. Warmed up for an hour or so we become much more engaged.
On the other side of the proverbial coin is the opposite: too hot and they can lose the life of the music. I've experienced this more than a few times when equipment stacks have been poorly ventilated. Let them cool down to normal operating temperatures and life returns to the music.
In the end, most equipment sounds its best when it's happily within its acceptable operating range.
As a rule of thumb, I like a minimum of 30 minutes minimum to get started. If the system's been on all day that works too (as long as there's proper ventilation).
As in most things the extremes are not where we want to be.