json_encode() non utf-8 strings?

So I have an array of strings, and all of the strings are using the system default ANSI encoding and were pulled from a SQL database. So there are 256 different possible character byte values (single byte encoding).
Is there a way I can get json_encode() to work and display these characters instead of having to use utf8_encode() on all of my strings and ending up with stuff like u0082?