This might give you some ideas, goes along with Mapman's suggestion relating to power !!!! I agree with Newbee's placement and tube suggestions and Mattmiller's wire statements. Where are your speakers positioned in relation to the front and side walls? System pics are helpful so people can observe the whole set up !!!!
http://www.stereophile.com/standloudspeakers/508ush/index.html
http://www.stereophile.com/standloudspeakers/508ush/index.html