I'm wondering the right place to ask this question.
What I'd like to do is to take a simple midi ear training app (with possibly vst~ output) that I wrote years back in Max/MSP 6 (I never bothered to upgrade from 6 given the cost and how little I used it).

You'll might find the cyclone library useful. It clones a bunch of Max objects in Pd. Go to Tools->Find externals and type "cyclone" to get it.

you could post screengrabs of your max thing. or you could list some of the objects maybe where it doesnt match .we could find work arounds. because it probably wont convert youll have to re-do some of it.

max has a free demo for 6 if you dont have it anymore.