Bullshit. Really. Your opinion, I will respectfully disagree because I have said exactly that and was shown to be wrong. If they use the filters on the DAC chip or have there own, also, makes a huge difference.
As I said, that is YOUR opinion, not an actual reality. I am not talking expensive DAC's but there are more out there than SMSL, Schiit (which are 2 gens behind the times and why they are cheap). Buy what you want but if your digital playback sounds bad to you, it is more than likely your playback system is the culprit (change out the DAC).