Humblehomemadehifi tested the CAST:
http://www.humblehomemadehifi.com/Cap.html
Sound: The CAST capacitor has all the same characteristics as the VSF but with added top-end clarity and together with that, more spatiality. They are (like the VSF) super natural, smooth, clear and open. The tonal balance is extremely neutral, especially audible with good recordings of acoustic instruments and the human voice, so maily with classical music. Like the VSF the separation of the individual instruments is very good and in an orchestra, the string section is a group of individuals rather than just a group. Soprano's have clarity without becoming hard to the ear, wind instruments (especailly the copper section) have that nice "metal" edge without becoming rough. Where in the past you had to choose between a Mundorf Silver/Gold/Oil (very good depth and imaging) or a Duelund VSF (very neutral presentation) you can now have the best of both worlds in the form of the Duelund CAST-Cu. I did find they needed a couple of weeks use to fully come to bloom, so give a chance to burn-in. My current reference!
http://www.humblehomemadehifi.com/Cap.html
Sound: The CAST capacitor has all the same characteristics as the VSF but with added top-end clarity and together with that, more spatiality. They are (like the VSF) super natural, smooth, clear and open. The tonal balance is extremely neutral, especially audible with good recordings of acoustic instruments and the human voice, so maily with classical music. Like the VSF the separation of the individual instruments is very good and in an orchestra, the string section is a group of individuals rather than just a group. Soprano's have clarity without becoming hard to the ear, wind instruments (especailly the copper section) have that nice "metal" edge without becoming rough. Where in the past you had to choose between a Mundorf Silver/Gold/Oil (very good depth and imaging) or a Duelund VSF (very neutral presentation) you can now have the best of both worlds in the form of the Duelund CAST-Cu. I did find they needed a couple of weeks use to fully come to bloom, so give a chance to burn-in. My current reference!