I'm recapping a vintage amp, and that amp has two larger caps at 2200uF @ 50V. I have sourced some possible replacements, and I'd like some insight into why these are SO different in size, and how I should think about that. (These are both new parts. Original cap not pictured. I know they are slightly different in capacitance--the schematic asked for one thing but the original part was another-- but I think the question here still stands since the specs are so close).
The big one is a Sprague Atom rated to 85°C. (data sheet here). The small one is a JWCO part rated to 105°C. (Data sheet here)-- it's over an inch long, which makes the Sprague huge at like 2.5"+ and way more diameter.
Now, I get that the JWCO is a sort of no-name commodity part that I don't want to use in an audio amplifier-- I get that. But even a Nichicon audio cap at 2200/50 is only going to be a bit over an inch long.
But what I don't get here is WHY these are so enormously different in size, and what's up with the Sprague? Small variances wouldn't surprise me at all based on materials and construction but this is not a small variance. Even the 50-year-old cap I'm replacing is much smaller than the Sprague (though not as small as the JWCO or a Nichicon).
Thanks for any insight. Piecing together my knowledge of components by example!