Marco you may be interested in these, and they have separate cathode feedback windings as well.
http://cgi.ebay.com.au/Ultralinear-...796616238QQcategoryZ50598QQrdZ1QQcmdZViewItem
Cheers George
http://cgi.ebay.com.au/Ultralinear-...796616238QQcategoryZ50598QQrdZ1QQcmdZViewItem
Cheers George