Question about order of PSU, switch

MakerNewbie wrote 07/17/2016 at 16:31 0 points

I'm retrofitting an old clamp-on desk lamp with LEDs. The original button switch (which I'd like to keep) is in the swivel head on the lamp. I plan to put the wall wart inside the lamp's metal base where the old ballast and transformers were located.

My options are:

1) Keep the wall wart on permanently energized with no load, and run the 12v output through the switch (this is the easiest option). 

2) Run the mains to the switch and back down to the PSU so it is only on when the lamp is in use

Are there any good reasons to do #2, or can I just go with option #1? The only concern I have is maybe whether the PSU will put off heat even without load, and how that might compare to the heat of the original parts, or whether the heat would eventually do in the PSU.

Also, my 12v 1Amp wall wart is sizeable, so I may have to remove it from the plastic casing before inserting it in the base cavity of the lamp (of course I'd make sure nothing could contact the metal enclosure. Not sure if the idea of taking the PSU apart  will affect anyone's input.

Thanks!!