Black Grand download is 44.1/24 in GS3, Kontakt, HALion and EXS24 formats (all of them, together). It's a sample library, not a virtual instrument. If your sampler will read one of those formats on the Mac then Black Grand is Mac-compatible. I use the Kontakt version on the Mac.
Thanks Amy, that's all I needed to know. Yeh I understand about the softsynth thing, I already have Sampletekk stuff, just was'nt sure of what bit depth the download material was. Again thanks for replying and clearing that up.