Musical Fidelity X-24K

I recently bought a 2nd hand X-24K and tried to connect to my NAD amp with great expectation. Unfortuately, it only produced woooooo noise. If I turned on volume high, I could barely hear the songs. I wonder if this DAC only supports 24bit Digital ouput from the transport. Otherwise it doesn't decode properly.
No it should work either way. You would need an interface to generate the upsample signal unless your tranpsort sends the 24/96 signal. There are lights on the front of the DAC that tell you what singal it is locked onto. The unit goes between the CDP and gets fed into your preamp or integrated amp. Are you sure that you have it connected correctly??

Happy Listening.
Sorry, I am new to audio tech. I don't understand what you meant by "You would need an interface to generate the upsample signal ". I checked my DVD player has a built-in 24bit decoder but the digital output doesn't send 24bit signal but 20bit instead. I connected the coaxial output from DVD to the DAC and it was locked to either 44kz or another higher up when I played a CD or DVD audio, the output jacks are connected to the CD input of my stereo amp. Do I need something else in between?
The DAC can receive an input of 16 and 24 bits. It has lights to tell you what it is receiving. If your CDP can only send a 16 bit signal then that is all the DAC will spit out. There are a few DIPs that take the signal and up it to 24 bits so that the DAC will use the upsample 24 bit signal.

Hope this helps.