You mentioned that you had a tube pre amp but did not mention the make and model. However if your looking to warm up your sound consider rolling some tubes. I have a Primaluna Dialogue 3 pre/amp and the sound was a bit hard w/the stock tubes. As a result I rolled my 4 12AU7's w/4 NOS military grade RCA black plate 6189/JRC 12AU7WA's and the change was smoother and less harsh better bottom. Rolling tubes could cost you anywhere between $30 to hundreds depending how many you need and the quality of the tube. NOS(new old stock) usually run more and military grade will last longer. Nice thing about tubes is you can change your sound w/out changing your gear in many instances.