Absolutely, it would be more convenient to convert and utilize the existing inputs. I'll likely end up doing this
I was hoping to avoid digital conversion and instead listen directly to the analog output from the turntable.
Also, since I'm learning about electronics and not too concerned about this particular item, I thought it could be a fun little project. I just needed some reassurance that it is possible in theory. However, after reading the datasheets of the different ICs, it doesn't seem very promising that any of the circuits would accept a line-level signal."