Controlling how many articles appear in your feed

before:
burned my wp feed at feedburner.
when i publish a new post, only that post shows up as “new” in feed aggregators.

now:
i installed better feed for my feed.
when i publish a new post, that post plus the last 9 (so a total of 10 for the mathematically challenged) are “new”.

um, how to get it back to behaving like before but still using better feed? thank you! 🙂