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Posts: 10911
Location: Bethesda, Maryland
Joined: December 11, 2000
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I have one foot in each camp; I do believe in identifying and using "good" electrolytics, when I pretty much have to use an electrolytic. But beyond that, I do not fret. I empirically chose to use the ELNA Silmic II, based on reputation, in an outboard PS I built for a Klyne 6LX preamplifier that I bought off ebay for cheap, because it had no outboard PS. I also used the same types inside the audio chassis, where Klyne uses electrolytics as decouplers around each stage. However, I also used a big fancy Nichicon inside the audio chassis, because there is no Silmic available in the >4700uF/50V value I required. Once having done that work, I would never think about replacing all those capacitors just to see if some other type might be audibly better. The Klyne sounds great. If I were to think of tweaking it, I would look elsewhere than the filter capacitors. Other "good" electrolytics with which I have actually built things include the Nichicon brand and ELNA Cerafine (no longer in production). Frankly, I have never been excessively impressed with Black Gates, but in fairness I never used the top of the line ones, WKZ, I think. I always thought the Cerafines were a better bang for the buck.
Yes, you CAN use a polar electrolytic for a coupling application. As I understand it, many inexpensive to mid-price solid state devices do that. In my Beveridge amplifiers, the circuit calls for a 10uF electrolytic as a coupler. It's shown on the original schematic as a polar capacitance. Because one of my amplifiers was acting up (oscillating) I dared not deviate from the schematic until I finally isolated the real problem. So, for a long time I used an ELNA Silmic II, 10uF/50V, as a coupler. Eventually, I bypassed that with a 0.1uF teflon film capacitor, and this is the only time in my experience where bypassing a coupling capacitor actually seemed to sound better than not bypassing. And now I've had the guts to use a bipolar Nichicon Muse in this application, no bypass. I actually do not think it sounds any better than Silmic + teflon. Next step would be to install some 10uF/100V polystyrene film capacitors that I was lucky enough to find, in place of the bipolars. Just for fun, I compared the ESR of the 10uF Silmic polar with that of the 10uF Nichicon Muse bipolar. The latter capacitor has a much lower ESR, which I have to think is desirable.
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