Electrolytic capacitor for audio in professional device!

[Willen]

I saw some of very high quality audio recording devices like mic preamp or audio interfaces. All of them have electrolytic capacitors. No film capacitors (known as the best for audio). They used SMD electrolytic there. What is fact? Do I get even more quality than 'professional' level if I changed them with film? But they are more than few uF rated and it's hard to get high value film.

 

[Nigel Goodwin]

I saw some of very high quality audio recording devices like mic preamp or audio interfaces. All of them have electrolytic capacitors. No film capacitors (known as the best for audio). They used SMD electrolytic there. What is fact? Do I get even more quality than 'professional' level if I changed them with film? But they are more than few uF rated and it's hard to get high value film.

It's mostly yet another fallacy, IF you wanted you could spend a LOT of money on supposed superior components (and a small number of people do), but it's pretty certain you won't be able to hear any difference, or indeed measure any difference.

I would suggest more of a concern would be the noise levels from all the high speed digital circuitry on those boards, which while small is still vastly greater than any possible capacitor improvements.

Funnily enough it's slightly similar to the tube amplifier thread running elsewhere, except that's a matter of audible and easily measurable drops in quality while spending a lot of money. The only reason I mentioned it, I had an EXPENSIVE valve amplifier in for repair at work a couple of years ago - that belonged to an old friend (he used to be known as 'Barrel' - but he's not called that any more ). Anyway, as well as spending X thousand pounds on this high end valve amplifier, he also paid £600 odd for a 'capacitor upgrade' to it as well.

I never found anything wrong with it, it was supposed to be intermittent?, but I can confirm it sounded just as good as a £49 mini audio system

 

[audioguru]

The first circuit shows 6 blue film capacitors on it.
When I worked for a Japanese PRO amplifier manufacturer, they used many non-polarized electrolytic audio coupling capacitors in all their products.

Most of my circuits use high input impedances then low value film capacitors are not expensive. Many high quality mic preamps have a low input impedance for dynamic microphones. Low impedance dynamic mics are used for the upper midrange peak in their frequency response to cause "presence" that is a form of distortion that they like.