I think it was Paul Miller in 'Choice many years ago who tested the output impedance of transprts and the input impedances of their matching DAC's. The Meridian 600 series was all over the shop (I can't remember if the two actually matched each other though) although I think the Linn Karik/Numerik in their first incarnation were pretty good, but it's a very long time since I read the group test reviews..

The general incompetance of much domestic kit really is evidenced by the fact that cables really do seem to make as much a difference as they do. As said above, get the impedance matching right, and many of these audible differences disappear.