If I were to go with an integrated tube amp to replace my Luxman 505ux (which has much better bass response with my Harbeths than the Rogue Cronus Magnum), I would check these out.
http://www.toneimports.com/lmaudio/501IA.html
http://www.audioresearch.com/en-us/products/integrated-amplifiers/vsi75
http://www.toneimports.com/lmaudio/501IA.html
http://www.audioresearch.com/en-us/products/integrated-amplifiers/vsi75