having done several TE with SMD ceramic and tantalum caps i assure you they dont add hum, they actually reduce it
i liken can replacement with SMD replacement to all the different "hacks" people were attempting to reduce Jailbars with NEC consoles. It wasn't until Tim Worthington, in my opinion a brilliant electronics engineer, approached the problem from a fundamental electronics point of view that we now have (what I believe to be) a universal solution (with explaination) to that problem.
When another brilliant engineer (Dave Jones) puts out a video explaining why replacing cans with SMD sometimes is a bad idea, and proves it with measurements on oscilloscopes and calculating on the white board using proven electronics equations; I listen.
I just wanted to bring this up because there are some really good modders out there, but it doesn't mean they're good electronics engineers that can design circuit boards from scratch. I for one know I couldn't.