This is exactly what I do and exactly what HT bypass does. Most people don’t understand HT Bypass.
HT Bypass is a way of sending the preamp signal from your HT system for the front 2 channels to a seperate input on your 2 channel amp. It is like switching to a different input when you want to watch a movie. You switch back for 2 channel sound.
The only thing you need is to make sure your HT system has pre-out for the front 2 channels and most all of them do.
One clarification. I don’t think I’ve seen an HT system with a digital out so you won’t use your DAC. However, the DAC in a good HT reciever is fine for movies. You’ll use your normal DAC for 2 channel sound.
Jerry
I will add that my amp does not have HT bypass. So I added it. HT bypass is an input directly to the amp. I added a set of RCAs and a couple of quality toggle switches so now I have an extra input for my HT. However, lots of preamps and amps have HT bypass. In SS I highly recomment the Kinki Studios EX-M1+ with a very nice HT bypass and excellent sound. clear like a tube amp. Yes, I’m a tube amp guy, we aren’t afraid to mod our amps.