||16th December 2009 05:51 PM
"Best" film cap you've never heard of?
At the risk of starting another cap war, I would like to introduce my new favorite, which might be completely unknown to those of you who care about such things.
Those of you who do not care, please withhold your sarcastic remarks. I am not the least bit interested in your engineering background, your skeptical nature, and your ability to determine every sonic aspect of a component based on a few measurements. If you don't believe in the fragility and fickleness of an electrical signal that is supposed to convey an emotion instead of a numerical value, please ignore this thread. In other words, put away your meters and scopes and listen to the music for a change, and spare us your pearls of wisdom and witty dismissals. I am well aware that the best cap is no cap.
In the process of building a pair of monoblocks, I installed many different brands of "identical" value (0.68mfd) caps in the DC blocking input section. The caps were always evaluated after sufficient break in (again, skeptics need not respond), which was determined simply by listening for when the sound of a new cap stopped changing. That time period varied for every different cap, from hours to weeks. Each monoblock always contained a different cap, so I was always comparing a different pair. I used stereo and monaural source material. Sometimes the stereo image was so badly affected that it was difficult to focus on the sound of each channel, but a monaural source always allowed me to focus clearly on the sound of each individual cap. Sometimes I would listen to only one channel at a time, switching back and forth after extended periods. I also switched amps from one channel to the other to ensure no room or upstream effects were distorting my tests.
After months of comparing, I finally selected the two which I thought sounded better than all the others: Mundorf SIO and Fostex copper/tin foil and film. These two caps are both superb components that competently convey much of the subtle information contained in music. The differences between them were far less than the differences among all the other caps I tried. After many hours of attentive listening, I developed a preference, but it was not a very strong one. Last night, I hosted two other audiophiles and we made a blind test between the two caps. We used lots of different music, stereo and monaural. At no time were they aware of which cap was in which amp. I swapped amps from side to side, and, once, didn't swap sides when I told them I had. At no time were they aware of my or the other person's preference. Their preference always followed one cap, despite my trying to fool them. All of us preferred the Fostex cap. We all agreed the difference was subtle, similar to that between two nice IC's or power cords, but significant enough to matter. Where the Mundorf was very detailed and allowed us to hear many volume levels and shadings of different instruments, the Fostex was similarly detailed yet smoother, with more spaciousness and depth, and somewhat better bass. The Mundorf was slightly flat in perspective compared to the Fostex, which gave more roundness to the sound of individual and groups of instruments and voices. The Fostex had a more realistic tonality where the Mundorf seemed slightly artificial.
I have never seen Fostex mentioned in any of the popular cap shootouts (where Mundorf SIO is usually rated very highly), so I thought I'd bring it to your attention. It's not a cheap cap, but it does cost slightly less than the Mundorf. I know there are lots of good film caps out there, and I didn't try them all. There might be better caps, but I think I'm done testing. I don't know where Fostex caps are available, other than Madisound.