akso, this is the one that i've got that i tried to replace it with which won't work
http://cgi.ebay.co.uk/SONY-100WATTS-...1%7C240%3A1318
edited to say:
some of these subs also come with the surround sound set up built inside them, they won't work with the amp either because i don't think they aredesigned to, so it needs to be an active sub only