PrimaLuna Preamp Upgrade Question

I've been using PL's for some years. I've found that so much of what I expect of my (integrated) amp depends on its tone, which in turn depends on tube selection. For example, if I want a full, warm tone, I'd use Tung Sol 6550's, and for a cooler tone, i.e. greater clarity etc, I use SED 6L6GC's. So if all you want to do is spend more money on your system maybe just some judicious tube rolling will keep you busy for a few years :-).

 But, FWIW, were I dedicated to going back into separates I think I would bite the bullet (cost wise) and go elsewhere.  

Re speaker set up, it’s really not possible to suggest a set up starting point as you have not really described your room, however tablejockey’s recommendation for the Cardas calculator is a good one as a starting point. Overall your end result will probably be optimum with your speakers further out into the room (mine are 5 1/2 feet) your listening chair well out from the back wall (mine are 4 feet) set up in a equilateral triangle or something close thereto (mine are 9 feet apart and my chair is 10 back from the plane of the speakers). The speaker are toed in substantially to reduce side wall reflections (but it seems you have plenty of space on the sides already). Another consideration is whether to put you speakers on a long wall or a short wall. I’ve always found the short wall better, but if you can, try both.

There, that you keep you busy. Getting your room right takes quite a bit of time. Although room treatments can be helpful, I would recommend that you get the fundamentals right before you start on ’treatment’. FWIW.