Concerning the "high enough current" flowing through the cap: In most measurements Bateman shows the AC voltage and DC Bias voltages applied to the cap, just as the load resistance.JR. wrote:I am not arguing for using electrolytic caps in the MC preamp input. I advocate designing such caps out of audio paths when possible (see Wayne's floating mic preamp to eliminate input caps), but it is worth trying to understand the application before making such a broad sweeping condemnation.
Bateman's excellent series on capacitors is stressing the electrolytic caps at high enough current to generate significant terminal voltage across the capacitors. Capacitor non-linearities express only when there is terminal voltage due to significant charging and discharging current. In a simple DC blocking application the capacitor is passing very little current, and developing almost no terminal voltage at any audio frequency. JR
When testing for instance a 10uF tantalum cap, the recorded graph mentions 0.3Volt applied to the cap in series with 10 Ohm. This cannot really be regarded as a significant voltage.
With the used frequency of 100Hz, only 1 mA rms is flowing.
Distortion however is huge.
A 100uF cap was tested with 0.1Volt/10 Ohm load , resulting in that case in a very moderate 3.5 mA rms, not exactly the kind of current flowing in "filter poles in a passive loudspeaker crossover".
However also in this case distortion is much too high to be used in the signal path.
Your accusation of "broad sweeping condemnation" is therefore completely unfounded and rather over the top.
Hans