Capacitor Musings Part 1
Compared to other metalized poly caps, Mundorf SIO seems to be at least 2-3dB louder(!) at the same volume setting with punch that slams harder and truer. This cap makes me very curious about the top-of-the-line Mundorf Gold/silver cap, which I happen to have sitting in front of me :)
Long-term living with the caps, however, confirms the greatness of both caps because music remains inviting, refined, and eminently enjoyable, as opposed to fatiguing, wearing thin, and distracting. Since audiophiles tend to obsess over the last 5-10% of differences, I will mention that Silver/Gold has a bit richer presentation from top-to-bottom with a bit creamier textures and a bit closer imaging. As one can imagine from this description, Silver/Gold doesn't quite seem to be as Nth-degree clean as VCaps but renders more proportion of recordings more tasty.
I do not believe detail resolution is any less than VCaps, but a tiny bit more harmonic "bloom" over the notes makes music both sexier and less pellucid at the same time. Some people will absolutely love this quality and call Silver/Gold much "better" than VCaps while others will absolutely declare VCaps to be the better cap for the same reasons. To throw more wrench into the equation, the optimal tube set for one cap is not the best set for the other cap and vice versa. Such is life.
I am also unable to directly compare Mundorf Silver/Gold to Mundorf Silver/Oil at this time due to my system configuration, but my preliminary sense is that the two are not all that different sounding, though the small amount of gold compound mixed with silver does seem to add just a wee bit extra harmonic richness and warmth.
The good news. This cap has incredible "low-loss" sound. One gets the impression every little detail comes through and that musical speed does not get impeded. Bass is taught, punchy, and treble extension soars; midrange seems linear. Its sound signature is what many audiophiles would think of when words like "neutral, detailed, honest, etc" are used, and they would be right, uh... sort of.
The bad news. Compared to an exquisite cap like Mundorf silver/oil, what is not coming through as well is the harmonic beauty of the music, the "soul" if you will: overtones upon overtones gently bubbling to the surface as the singer sings the words and the trumpet makes those aching notes. In addition, each instrument/voice does not seem as developed 3-D wise. Through Zn, they seem more 2-dimensional and "flat." Combined with its more dry (less bloomy) presentation, there is less involvement.
So I have mixed feelings about Mundorf Zn. Its sound is technically superior and "uncolored," an order of magnitude better than pretty much any other "cheap" cap you can buy. If I were designing/building a transparent preamp, I can see using the Zn in many places, judiciously mixing them with tube magic elsewhere to come out with supreme results. If you have a preamp/amp that's more dry and matter-of-fact to begin with, I would advise against the Zn.
Actually, I think the Zn may lend itself incredibly well as bypass caps in speaker crossovers due to its qualities. I'll get to that eventually.
In direct comparison to VCap Teflons, SP (Sonicap Platinum) was a bit richer and a smidge creamier. We're talking about somewhat subtle differences, but SP was definitely a bit denser, darker, therefore subjectively a wee bit smoother through the midranges. Some will almost recognize a bit of this as found in a good paper-in-oil cap, minus the treble roll-off or bass slowness, of course.
The VCap still does come across as a teeny bit more transparent and lit-up, and what's somewhat special about the VCap is the fact it sounds *consistently* transparent/lit-up throughout its ranges, especially in the critical upper-midrange to low-treble transition; there's no peaks or bumps here even though the whole range is better lit-up.
With SP, even though everything else seems a bit smoother and richer, there seems to my ears a very narrow band, somewhere at the highest end of female vocal sibilance to top-hats, that appears to have the tiniest bit more "sparkle" than the rest of the range. I only mention it b/c it is a difference.
Overall, SP is a nice alternative to the VCap Teflons and costs less. Just like anything in audio, some systems will synergize better with one or the other. For those who have listened and think VCap is a bit too literal or "sterile" (I don't personally) in their systems, Sonicap Platinum is a viable choice.