Hello, no, the device has no memory... i.e. you should get one, preferably an SSD, because it's quiet and doesn't get warm. You also need a memory if you want to save stations on the radio, which is a bit strange. But you can also put a 64GBit stick in the back, for example, and then you can save radio stations or one or two music files. Or you can access a NAS (server) via the internal network, for example, and then you also have music from the "can". I operate the device like this. I put the stick in the back and take the music from my NAS.

Hello, The X12 has no internal memory. However, it has a flap on the right side and a slot in which you can easily install a HD, all connections are present and the installation is really uncomplicated. I use the device with a 2 TB HD (WD RE (2000GB, 3.5", Server, Workstation for 153.--), this is very robust, as it is suitable for servers and absolutely noiseless. It would have room for over 2000 CDs. Actually, almost any HD with even greater capacity can be installed.
I would not install an SSD, as it is too expensive and an exaggerated luxury for this application.