If your goal is simply "discovery", an Auris BluME HD bluetooth receiver will do the trick at just over $100. It is bluetooth and you are using Spotify, so it will be a lossy digital stream and sound quality will not be optimal. However, I use one and I can tell you it is plenty good enough for me in my system. I use it regularly for the exact application you mention - discovery. For me, Spotify Premium, and their "Discover Weekly" playlist, have resulted in more "new to me" music than any other source. My second most successful source for new music has been streaming Radio Paradise's internet radio, which you can also do with the Auris BlueME HD.
To use the above you just need to plug the analog output of the Auris BlueME HD into a spare line-level input on your integrated amp. From there, pair any bluetooth enabled device to the Auris, go the the app of choice (Spotify, Radio Paradise, etc.) and play. It will transmit from your device (Kindle, mobile phone, etc.). Lastly, if your integrated amp has the DAC module in it, you can connect the Auris using a digital cable and use the DAC in your integrated amp. BTW, I do this in my system and there is a marginal improvement in sound quality using the external DAC vs the internal DAC in the Auris.
Easy, Peasy, only $100-ish dollars and works great. Likely won't match the SQ of your CD setup, but perfectly fine for discovery and non-critical listening.
To use the above you just need to plug the analog output of the Auris BlueME HD into a spare line-level input on your integrated amp. From there, pair any bluetooth enabled device to the Auris, go the the app of choice (Spotify, Radio Paradise, etc.) and play. It will transmit from your device (Kindle, mobile phone, etc.). Lastly, if your integrated amp has the DAC module in it, you can connect the Auris using a digital cable and use the DAC in your integrated amp. BTW, I do this in my system and there is a marginal improvement in sound quality using the external DAC vs the internal DAC in the Auris.
Easy, Peasy, only $100-ish dollars and works great. Likely won't match the SQ of your CD setup, but perfectly fine for discovery and non-critical listening.