Looking for some help with reading a can capacitor

[quadaptor]

I’m a novice with this stuff so I’m hoping someone can help me out. I have an old Heathkit AA 30 tube amp that I’d like to recap and figured it would make a good entry level project. The can capacitor is marked:

40-450 / 40-450 / 40-350 / 50-50

B-25-100

How exactly do I read this and can I find a modern can cap to replace the original? Many thanks in advance for any help.

 

[ivandezande]

First number is the capacity in microfarads, the second the voltage, e.g. the first is 40uF 450V. It's a 4 section cap. The B-25-100 I'm guessing is a ID mark. google is your friend for finding a replacement but I just use individual caps as cans are expensive and have bad specs.

Also tube amps are not really a good entry level project.

 

[quadaptor]

Thanks. This amp is pretty simple and I’m just looking at replacing the caps. And my interest is in tube amps but I could be underthinking the situation. Any recommendations for caps? Thanks again.

 

[quadaptor]

Also, can you use a cap with a higher voltage rating as long as you keep the uf rating the same?

 

[gadget73]

higher voltage is fine, within reason. I wouldn't use a 500v cap in place of the 50v, but changing all of the higher voltage ones to 450 or 500 is fine.

value is usually shifted to whatever the modern is. 40 and 50 becomes 47uf.

Hayseed Hamfest makes modern cans in whatever values you need. If they don't already have a suitable one listed, they can make it. The other option is cutting and stuffing yours, or installing new ones underneath, and just leaving the can abandoned in place.

 

[quadaptor]

Thank you very much!