Raspberry Pi 2 model B with HiFiBerry Digi+ HAT installed in a smart HiFiBerry metal case, fully configured and up-to-date with the last ropieee version which supported the model 2 as well as a regular 5V, 2.5 A power supply.
In case you should be concerned about the old model 2, this is more than sufficient from a memory and CPU perspective. To be honest given the lower CPU frequency I always felt it to generate even less noise than P3/P4s (but your mileage might vary).
I’ve used this to stream via Ethernet and connect my studio speakers via RCA coax (S/PDIF also available) but now no longer need this as I upgraded to a more powerful solution.
The HiFiBerry Digi+ is a high-quality S/PDIF output for the Raspberry Pi. It uses the I2S sound port that connects directly to the CPU without the need for an additional USB conversion. It supports sample rates up to 192kHz/24bit. The standard version features an optical output (TOSLink) and an electrical output.
You can either power this ensemble using the provided power supply (MicroUSB) or you can further improve sound quality by using the power supply modification I did which allows to power the HAT directly using a DC 5,5 x 2,1mm connector.
Price 100 € (up for negotiation)