I just disconnected the 8-track. It has RCA connectors. Then I ran https://www.amazon.com/Monoprice-100665-3-5mm-Stereo-Cable/dp/B001V5VCNM to an Echo. I've also added some vintage Wharfedale Opal 30's to the auxiliary speaker connects to punch up the bass a bit. You got one hell of a deal for .50!
No, something like this: https://smile.amazon.com/Monoprice-100665-3-5mm-Stereo-Cable/dp/B001V5VCNM/ref=sr_1_4?crid=2Q8THBRB1QXX2&keywords=3.5+to+rca&qid=1669067226&sprefix=3.5%2520to%2520rca%2Caps%2C65&sr=8-4
The 3.5 plugs into your computer, the RCA plugs into your receiver
No it doesn't. Just get the cheapest one you can get. The DAC of your laptop/desktop should be pretty good enough, you may not even need the Modi later.