I’m sticking this up in the off chance it’ll turn up in someone’s Google search one day and save them some time or money.
If you found this you probably did what I did which was forget to turn off your NAD 315BEE amplifier. And then one night, at 3am, you woke up to find your speakers buzzing REALLY LOUDLY. Even when you put the amp into standby, which is odd.
The two large 10000μF smoothing capacitors have blown and need replacing. If you’ve got a soldering iron and stable hand you should be able to do it yourself.
If you’re in the UK RS stock these replacements which are the right specification and size. You can find guides on YouTube for how to swap them.