Nad M51 + usb conditioner?

+1 the iUsb also helps with cleaning up the output of my iLink converter with my M51, so give it a try. I recommend Fred at Stereodesk. The USB cable also has an effect - I'm using the Nordost Blue Heaven with very good results.

I have a NAD M51 and tried a few USB converter on it. It benefits quite a bit from one - which is not unusual - most do. The best is an Off-Ram, the best value an Audiopholleo.

Thanks
Bill

Yep. I use AP2+PP to connect my linux nas to m51 and love the result. AP2 +PP sounds fresher while OR5 delivers denser textures. Both are great for m51 depends on personal taste and system.

Couldn't you just use the HDMI input from computer to NAD M51 instead of the USB?

I have one question here:  I have the NAD M51 in my system and use it as a preamp/dac. I'm also a computer scientist and have pretty good knowledge of how data is transferred between computers.  How exactly do you think an USB cable affects sound quality?