Tweaker's Asylum

Posted by Dave I (i) on July 26, 2000 at 08:10:39:

In Reply to: Re: Capacitors don't matter ... posted by BFitz on July 26, 2000 at 07:29:54:

The film caps in my case and in the single ended tube guys case are preceded by large value chokes which is more work and expense but enables the building of a component such as preamp, D/A convertor, turntable PS or even low power amp with NO electrolytic capacitors. I can tell you from my own experimentation that introducing even the highest quality electrolytic into such an electrolytic-free system is like turning off the magic switch. The gains are sometimes staggering from eliminating such a large source of irritation.

I think a lot of the problem is due to the delayed resonance problem that the Jung test hinted at. Energy is lost to the movement of the plates inside the capacitor setting up radial waves from the center to the outer case and then resulting reflections back into the core. The highly etched aluminum plates, which are like ceramic in the more miniaturized ones, can resonate at high and not very damped frequencies and this energy in turn causes changes in the capacitance and thus affects the voltage across the capacitor. The capacitor value versus time will be a very complex function related to the exciting voltage and all the individual properties of the parts it is constructed from. And when used in the typical capacitor input power supply, they are subjected to very high current pulses which probably excites many internal resonance modes. All conjecture on my part and no evidence to back it up except based on these ideas, capacitors wrapped in a layer of lead viscoelastically coupled to the case have proven to myself and others to be a dramatic improvement when used in power supplies and most other areas that are not "directly" handling an audio signal (power supply caps of course do supply all the audio current and so I think should be considered directly in the signal path).

Dave