These all appear to be 15,000 microfarad, 50V electrolytic capacitors, of the "snap in" construction type.
Replacements will be available at Digi-Key or Mouser, etc. In ordering replacements, first measure to determine the diameter and height of the existing parts. Look carefully at the specifications of the ones you order to make sure they are within the dimension limitations of the originals or the replacements will not fit on your circuit board. Any good industrial brand will be fine, Panasonic, Nichicom, Chemicon, etc. These are just being used for some raw power supply application and musical quality will not be an issue.
I should note that the minor top of case bulging is not abnormal for this kind of capacitor after long use in a hot environment. Unless you know they are defective, I would not recommend replacing them as you will have to remove the circuit board to do that and the chances of doing accidental damage could be high. Leave a sleeping dog alone unless it is barking at you. When these fail, the unit will bark at you for sure.
Given this configuration of eight of these capacitors and their rather low voltage rating, I suspect they are likely paralleled together to provide a huge low voltage supply in your unit, maybe a tube heater or solid state supply of some sort, certainly not for high voltage vacuum tube B+.
Best regards,
Frank Van Alsitne
