The best 1N4001 rectifier diode upgrade

I accidentally touched a nearby capacitor with my soldering iron and smelled something. I hope I did not break the capacitor.
That depends on the cap. If you burned the sleeve on an electrolytic cap then its no problem. If you physically melted a chunk out of a film type cap then you might have damaged it depending how deep the damage goes.
 
Well the worst performing diodes for typical linear power supplies for audio are actually way better than the best as long as a snubber is applied.

And don’t take my word for it, that was the conclusion of testing done by an esteemed and generous member here.