Cool that you've replaced the can cap. The rectifier diodes are most certainly germanium diodes that are horridly noisy, especially by now! If I'm not mistaken, Handmade Electronics still has some Philips BYV96E HEXFRED diodes, which have been discontinued. They are definitely superior to 1N4007s, but also much more expensive. It's very difficult to find axial leaded HEXFREDs nowadays. All are TO-220 case style. 1N4007s will work just fine in a pinch however, and they are still better than the vintage types.

The problem with replacing the rectifier diodes is that the voltage will be even higher, as modern silicon diodes have lower forward voltage drop than vintage germanium types. So, you'll first have to fix your voltage problem and change diodes before adjusting the first power supply resistor value.

Let us know what the voltage problem was when you find it.

Thermionic