A couple simple ideas that are cheap:
3.5 mm to rca direct from the computer to the preamp. Depending on the cable its a $15 to $50 investment:
Best Buy sells an affordable but decent bluetooth adapter for $60.
You can use the headphone adaptor and use the phones audio out: $10 for the usb-c or lightning to headphone and a 3.5 mm to rca for the preamp: Then you can experiment to see if the quality is any good. If you purchase from Best Buy, you have 2 weeks to experiment. If the quality isn't good just return and shell out the big bucks for a higher end option like a blue sound node which supports Tidal or Qobuz both which give you a hi rez option vs u-tubes low rez option.
3.5 mm to rca direct from the computer to the preamp. Depending on the cable its a $15 to $50 investment:
Best Buy sells an affordable but decent bluetooth adapter for $60.
You can use the headphone adaptor and use the phones audio out: $10 for the usb-c or lightning to headphone and a 3.5 mm to rca for the preamp: Then you can experiment to see if the quality is any good. If you purchase from Best Buy, you have 2 weeks to experiment. If the quality isn't good just return and shell out the big bucks for a higher end option like a blue sound node which supports Tidal or Qobuz both which give you a hi rez option vs u-tubes low rez option.