Most signal path/timing capacitors are of stable types such as film or C0G ceramic. However, size and cost force an upper limit on this -- C0G caps out at 10-100nF, while film caps can manage up to 1-10µF albeit at a severe size penalty -- this isn't enough to cover things like audio coupling capacitors and large timing capacitors, which may be 47µF or more. In the "bad old days", the only choices for these tasks were wet aluminum (bulky and with poor tolerances) or MnO2 tantalum (intolerant of reverse polarity but more precise) electrolytics. However, modern technology has given us more options for this -- conductive polymer electrolytes are now in common use with both aluminum oxide and tantalum oxide grown dielectrics, and niobium oxide based capacitors are a niche product as well.
Which of these technologies for large capacitance/high-CV capacitors, old or new, provides the best performance in terms of:
- stability (for timing applications)
- not distorting coupled signals or introducing excessive noise (for signal chain apps, such as audio or other low frequency signals)?