Nippon Chemi-Con KMH v.s. Rubycon USR
funny, because personally I wouldn’t use anything less than the nichicon HE series for the power section, simply because they’re not that expensive, I’ve got a stockload of them, and because low ESR is probably most important in the power section and usually unimportant elsewhere.
However, the audio section most logically would be more effected by capacitor quality, so they do need to be taken care of–it’s just that low ESR isn’t something that should make a difference in most circuits. I’d look at dielectric absorption/dissipation factor as the criteria for quality–but then again, almost all electrolytics exhibit pretty bad qualities with respect to these two characteristics (except maybe blackgates/etc, but you’d have to check the datasheets to make sure). This does get close to the audio voodoo stuff, so I usually don’t bother much with electrolytics in the audio section. Actually, now that I think of it, most of the circuits I’ve made simply avoid electrolytics whenever possible, so I’ve never really had to bother with them.