After many years of research and development they decided
to improve upon the original VSF by applying the elaborate
manufacturing process used in making the CAST version.
Using high purity copper foil with a wax impregnated
dielectric and treating with their own anti-resonance
CAST material the RS series was born.
These capacitors approach the CAST performance in a
number of ways, but at a lower cost.
outer lead out, closest to the edge of the capacitor,
is connected to the outer foil and as such should be
connected to the lowest impedance path to ground.
After many hours of burn-in time the main thing that
I kept writing about in my notes was how natural the
Duelund RS-Cu sounds. This is one of the few capacitors
with which I didn't have the urge to do some fine-tuning
or mixing with other types / brands to reach an optimum
result. In all the loudspeaker crossovers I tested them
in, they just sounded so logical everytime. It didn't
seem to matter if the tweater had a textile, magnesium,
ceramic or beryllium dome - the Duelund RS just portrayed
the sonic signature of the tweeter as it was. Nothing
added, nothing hidden, no need to tweak, a real no brainer.
Are we then looking at a CAST-Cu in disguise? No, the
CAST-Cu still is the no-compromise capacitor with a
blacker back-ground, making it more silent than the
RS. Also the RS-Cu doesn't quite have the same image
depth as the CAST-Cu. But like I stated earlier, the
Duelund RS Copper Capacitor is a real no brainer, once
you have put this capacitor in your loudspeaker crossovers
you will never need to tweak again! Everything just
sounds so logical.
some further info: http://www.humblehomemadehifi.com/Cap.html