Hi folks, i got some problems with my C47 preamp. I use it to play Hi-Res files via USB from my iMac. After connecting the C47 with my iMac the settings of my computer detects a C52 and no C47. Strange!! The internal DAC of the C47 can only handle 64 and 128 DSD files - no 256 DSD files. My program Audirvana Plus 2.3 only shows the option 64DSD and 128DSD - 256DSD isn't activated and cannot be chosen. Is that a problem coming from my early firmware version?