I am trying to evaluate whether to use tantalum versus OS-CON aluminium electrolytics as the output decouplers for some linear postregulators after a (relatively low noise) switcher. This is for a high gain amplifier that will be operating down to audio frequencies. I've come across references to aluminium electrolytics being noisy, but no firm details (kind of odd as there are lots of details about ceramics' problems under bias, wet vs dry tantalums etc). There's also some references to "low noise" aluminium electrolytics for audio work, but I don't know whether to take them seriously as audiophools believe all kinds of weird stuff. So, can anyone advise if aluminium electrolytics - specifically low ESR solid electrolyte types - have some kind of noise problem? I know tants are NOT microphonic but I've not come across any info about electrolytics and microphony one way or another.
Assuming they do not, I favour them over tants because their ESR is lower, I get the impression that tants' ESR is poorer at low frequencies, and I can get electrolytics at higher voltages (I like to run caps at about double their rated voltage under the impression this improves their reliability). The load on these linear regs will be fairly constant, so ripple current will be low.