If you have an Oppo or similar player a simple method is to rip the CDs to a portable hard disk using a program like "Exact Audio Copy.". They can easily be played them through an Oppo via USB directly and controlled from your phone.
Or you can use a lap-top to play them through any DAC that has a USB input. If it doesn’t have USB you can use a USB to spdif converter. If you use a program like JRiver you can rip them even more conveniently and also control from your phone.
Or you can use a lap-top to play them through any DAC that has a USB input. If it doesn’t have USB you can use a USB to spdif converter. If you use a program like JRiver you can rip them even more conveniently and also control from your phone.