Usually has to do with newer digital decoding formats which are added to later models.
Comparing the on-line specs of the RSP-1066 and 1068 for example, it looks as though both models have the same decoding formats but the 1068 has the addition of Dolby Prologic IIx, DTS96/24, MPEG Multichannel and LPCM (up to 192K). The RSP-1069 has the addition of DVD-A and HDMI-HD formats.
That's all I can see from comparing the specifications. Hope that's useful info for you. My system has three major Rotel components so I guess that makes me a Rotel loyalist !!
Comparing the on-line specs of the RSP-1066 and 1068 for example, it looks as though both models have the same decoding formats but the 1068 has the addition of Dolby Prologic IIx, DTS96/24, MPEG Multichannel and LPCM (up to 192K). The RSP-1069 has the addition of DVD-A and HDMI-HD formats.
That's all I can see from comparing the specifications. Hope that's useful info for you. My system has three major Rotel components so I guess that makes me a Rotel loyalist !!