Nope, you can't actually hear these noises, but rather it actually decrease the performances that you can get out of your transport. They could come under different forms and types, could be harsh treble extensions or bass extensions to fall flat on it face, or distortions in complex passages. Every little things do count. I was just speaking out of theories, some facts, and never actually want to bother with making any used cellphone into a transport.
I can, however, share the experiences that I have between Sony Walkman Zx2 and WM1Z. Both can be connected via the same Dock to be a digital transport, and in fact there are differences between them. Wm1z has better treble extensions and presentations. Very hard to believe but it is what I observed, though, would it be worth thousands of dollars differences ? Nah....could I get another cheaper transport that do what Wm1z do ? Don't know....LoL if my money was unlimited ....maybe