Have a look at the 1969 vintage Sony “88” bookshelf amp/tuner/decoder set at my office. I stream music from my Mac to this little amp whenever I’m at work for some years now.  I have two small Magnat speakers and a Yamaha subwoofer connected and vistors are always amazed about the great sound quality of this set. But this morning, no music but only a loud hum from the speakers after power on. After half a century the two 2200μf / 25V caps in the power supply of the TA-88 had enough of it all. Two new capacitors from the local electronics store for a mere 3 euros in total, half an hour’s work, and it plays like new again. Love vintage audio gear!