I have just removed the wrap wire from an Argentine string and the core seems to be hex not round. I had a luthier and an engineer have a look with a magnifying glass and they both confirmed hex core.
People have talked about the pre-New Concept Argentines sounding and feeling much better, although maybe not lasting as long. Is it possible this is the point they changed from round to hex? If so does anyone know when the new concept strings were introduced?
Interestingly the Savarez website makes no mention of round or hex cores.
Looking forward to opinions on this as the round cores seem to be a big selling point for Argentines.