Volleyguy, it appears we are hearing the same things with the CAST caps. As good as they are, and overall they are the best sounding cap I have ever used, the CAST caps are not perfect. We both notice less air and sparkle compared to some other caps.
It appears you think this character may be a good thing, that the CAST has less "resonance" and is actually more accurate. I don't know about that. Perhaps comparing the copper CAST to a silver CAST would help to clarify the situation. Even better would be a fair A/B test against a direct wire. If done right, this would tell us whether the copper CAST is lacking in air and sparkle or simply telling the truth.
In any case, just speaking for myself, I am not all that interested in trying to understand the physics behind why one cap sounds different from another. The only thing that matters to me is how it sounds. Even more to the point: how it sounds in my system. We are just hobbyists, not manufacturers, so we don't have to worry about how something might sound in a different system, only our own. From that perspective, I will stick with my observation that when I use a CAST cap I notice less air and sparkle. In practice all that means is that I need to balance out the overall tonal balance through other means, I.e. Another cap somewhere else or perhaps a resistor change somewhere to offset the effects of the CAST.
I would definitely be careful about using too many of any single type of cap in one's system because the colorations become much more obvious. This applies to CAST as well as any other cap type.
It appears you think this character may be a good thing, that the CAST has less "resonance" and is actually more accurate. I don't know about that. Perhaps comparing the copper CAST to a silver CAST would help to clarify the situation. Even better would be a fair A/B test against a direct wire. If done right, this would tell us whether the copper CAST is lacking in air and sparkle or simply telling the truth.
In any case, just speaking for myself, I am not all that interested in trying to understand the physics behind why one cap sounds different from another. The only thing that matters to me is how it sounds. Even more to the point: how it sounds in my system. We are just hobbyists, not manufacturers, so we don't have to worry about how something might sound in a different system, only our own. From that perspective, I will stick with my observation that when I use a CAST cap I notice less air and sparkle. In practice all that means is that I need to balance out the overall tonal balance through other means, I.e. Another cap somewhere else or perhaps a resistor change somewhere to offset the effects of the CAST.
I would definitely be careful about using too many of any single type of cap in one's system because the colorations become much more obvious. This applies to CAST as well as any other cap type.