It's a marimba alright, but I wouldn't say "high notes," kind of the opposite (but I guess it depends on exactly where/what part of the loop; you weren't very specific).
The DX7 marimba isn't all that bad, actually. I'd add some appropriate reverb. The "banjo-kazooie" marimba is pretty stinky, and definitely sounds like a ring tone.
It is basically a large, wooden xylophone. If you wanted to experiment with different substitutes, you could try xylo, vibraphone, glockenspiel, balafon, or even boobams (with a yarn mallet).