I once heard Robert Asprin read a Skeeve and Aahz story and after that, whenever I read one on my own, I'd hear his voice. Same after hearing Parke Godwin read an excerpt from WAITING FOR THE GALACTIC BUS. It fades after a bit, but my theory is that, when you hear a writer reading their own story, in a sense you get a "truest to the source" interpretation of the story. All the emphasis is where the writer intended, the intonation of the voices, the pronounciation of the names. Sometimes I wonder if that's what tends to remain, rather than strictly the writer's voice. As you pointed out, reading a Yamada story was different, and you've never heard me read a Yamada story.