The 6R8 resistor in the top of this picture
http://www.a2bdjs.com/images/crossOverParts.jpg
and this one
http://www.ebay.co.uk/itm/20W-6-8k-...883?pt=LH_DefaultDomain_0&hash=item3f0972f6d3
or this one
http://www.ebay.co.uk/itm/20W-6-8-o...964?pt=LH_DefaultDomain_0&hash=item35b1b02dbc
http://www.a2bdjs.com/images/crossOverParts.jpg
and this one
http://www.ebay.co.uk/itm/20W-6-8k-...883?pt=LH_DefaultDomain_0&hash=item3f0972f6d3
or this one
http://www.ebay.co.uk/itm/20W-6-8-o...964?pt=LH_DefaultDomain_0&hash=item35b1b02dbc