Or: How not to solder / How to annoy people by saying “can” as many times as possible.
These Superex Pro-B VI studio headphones from the 1970s belong to my grandpa, and sound amazing, but only when they work. Which, unfortunately, was not very often. I looked around online, and it’s apparently fairly common for the capacitors to die with age. So I replaced each (0.0025 uF) with the closest value I could get hold of (0.0022 uF).
Let-down noticed after a few hours: It didn’t fix the problem. But at least that’s two components that should last longer now. But if it’s not the capacitors then it may well be the custom-wound transformers in each ear, which are obviously not made anymore. Oh well, it gave me an excuse to make a casual camcorder/chatty video for the first time in a while.