I'm really happy with my system except for one small thing. I wish vocals were just a tad more present and detailed. With every improvement; be it cables, component, cartridge or isolation I'm always satisfied with the results except for this one thing. I'm not even looking for a dramatic change. With pretty much every lp or CD I just wish I could ask the singer to move towards the mic another inch or two. Will swapping the 12au7 in the preamp spot of my integrated amp help me? I'm using a new production Gold Lion 12au7. Again, I'm very satisfied with my system-it's listed in my profile-except this one little thing. Thanks in advance.