Maybe I'm missing the point but it *sounds* fine to me. Your source has, what sounds like vibrato, or amplitude modulation anyway, and if you view the echo chips output you will see what looks like amplitude modulation as the repeats are added to the original sound.
Perhaps a better test would be to send a sine wave of short specific length into it, with feedback (and low delay time, say 50ms), and capture the output, which sohuld show bursts of your original signal with decreasing amplitude and increasing distortion (after a few repeats this chip will distort the signal, like most echo guitar pedals do).
I'm not suggesting the chip isn't "fake" but so far I haven't seen or heard the problem you say you have. That doesn't mean it isn't there, just that your tests dont' convince me.