I currently own both a Ref CD7 with the power supply upgrade and a DAC 8. The rest of my system is also all ARC, LS27 and Ref 110. I purchased the DAC 8 to stream music from a laptop. The DAC 8 is all solid state while the Ref CD7 is tube including the power supply. I have played around with the system in the past and prefer the CD7 to either the CD7 as a transport with the DAC 8, or streaming red book through the DAC 8. One nice thing about the DAC is because it is solid state it can be left on so it does not need to warm up. If it were me I would look for either a used Ref CD7 with power supply upgrade or if possible a CD8. If you also want to stream music then you might want to still consider the DAC 8.
ARC CD 3 mk II upgrade with DAC 8
My current gear is all ARC which includes a REF 3, CD 3 MK II and REF 75. In the continuation of ongoing improvements, I consider my digital source as the next component for upgrade. I have been considering the CD 6 or a used CD 7. Recently a friend purchased a CD 9 and has offered me his DAC 8 at a very reasonable price. Using my existing CD 3 as a transport in conjunction with the DAC 8 is an option. Any recommendations or thoughts on this would be appreciated. thanks