As for laptops: http://archimago.blogspot.nl/2013/04/measurements-laptop-audio-survey-apple.html
Their inbuilt DACs are mostly evil, but as a usb source they are fine. The biggest issue with desktop PCs is their fan noise, although here the new generation of small Intel Nuc computers in fanless cases can be a good option, as would be a Raspberry Pi if it is just for the music playing: http://archimago.blogspot.nl/2017/01/measurements-raspberry-pi-3-as-usb.html
For the OP, I think his best bet is to get a Chromecast Audio for a few dozen dollars, connect it to the analogue input of his current system, and experiment with streaming services to see if he likes this way of listening. If he does, and only then, it is time to think about the electronics. I would go for a DAC with multiple digital inputs and variable output (e.g. the Pioneer U-05 or the Benchmark DAC 3), using a Chromecast Audio and its digital output as a streamer (and also the digital outputs of the television and the disc player). If video is important, an Oppo 205 will do the same job of DAC and preamplifier and will also play cd's. Plus a beefy solid state power amplifier.
With the Chromecast Audio there is one thing to consider if using the analogue output. You can choose between a Normal and a High Dynamic Range setting. You would think more dynamic range is always better, but the snag is that this is actually not a dynamic range setting, whatever the misleading title. The difference is just the output voltage, with HDR equal to the 2V Red Book Standard. If your rca line input is for 2V, choose this one, but many analogue inputs are more sensitive, in which case you get a cleaner less clipped sound with the lower output setting.
By the way, this sensitivity matching problem is also an issue with many cd players that should have the 2V output, but are often even hotter. If your amplifier has the traditional more sensitive inputs, you get clipping distortion, which contrary to what you may expect is quite common, and may in part explain the reticence about ’digital sound’. A telltale sign is if you do not have to turn up the volume very far to get a loud signal. The solution is simple: insert an inline attenuator or an attenuation cable.
Their inbuilt DACs are mostly evil, but as a usb source they are fine. The biggest issue with desktop PCs is their fan noise, although here the new generation of small Intel Nuc computers in fanless cases can be a good option, as would be a Raspberry Pi if it is just for the music playing: http://archimago.blogspot.nl/2017/01/measurements-raspberry-pi-3-as-usb.html
For the OP, I think his best bet is to get a Chromecast Audio for a few dozen dollars, connect it to the analogue input of his current system, and experiment with streaming services to see if he likes this way of listening. If he does, and only then, it is time to think about the electronics. I would go for a DAC with multiple digital inputs and variable output (e.g. the Pioneer U-05 or the Benchmark DAC 3), using a Chromecast Audio and its digital output as a streamer (and also the digital outputs of the television and the disc player). If video is important, an Oppo 205 will do the same job of DAC and preamplifier and will also play cd's. Plus a beefy solid state power amplifier.
With the Chromecast Audio there is one thing to consider if using the analogue output. You can choose between a Normal and a High Dynamic Range setting. You would think more dynamic range is always better, but the snag is that this is actually not a dynamic range setting, whatever the misleading title. The difference is just the output voltage, with HDR equal to the 2V Red Book Standard. If your rca line input is for 2V, choose this one, but many analogue inputs are more sensitive, in which case you get a cleaner less clipped sound with the lower output setting.
By the way, this sensitivity matching problem is also an issue with many cd players that should have the 2V output, but are often even hotter. If your amplifier has the traditional more sensitive inputs, you get clipping distortion, which contrary to what you may expect is quite common, and may in part explain the reticence about ’digital sound’. A telltale sign is if you do not have to turn up the volume very far to get a loud signal. The solution is simple: insert an inline attenuator or an attenuation cable.