From The K3ZRF Estate, there are two
dbx brand audio processors that would be dandy for
your AM station.
In this case, the lower-numbered model name is actually the more capable unit.
http://www.dbxpro.com/166XL/The other unit has good compression capability but not the fast-action peak limiter, which means a lower price.
http://www.dbxpro.com/266XL/Both are current production, very clean, and have owner's manuals available for free download, online:
166ftp://ftp.dbxpro.com/pub/PDFs/Manuals/English/dbx166XLManualA2.pdf266ftp://ftp.dbxpro.com/pub/PDFs/Manuals/English/dbx266XLManualA2.pdfAll proceeds go to ZRF's widow, Pam.
Interested: Make offers via private message (PM) or text me 202 841 3208