@SwiftOnSecurity Ah, yes. The power supply for my home made amplifier (which didn't survive a lightning strike on the fishpond a number of years ago) was very crude and basically relied on a pair of 20,000uF capacitors (which was big in those days).

Yes I put some bleed resistors across them (yes with a high power rating) but it was still a good idea to leave that power supply switched off for an hour or so before doing anything to its insides.