Wow! Lots of great ideas and a couple breakthroughs for me. One, my CD player - a Rega Planet - has digital out which I didn't realize. The vinyl machine is a Rega Planar 3 with their 300B arm . . . it replaced a Planar 2 I found at Goodwill for $19...:8)
As I mentioned earlier, the basic system I have, I love. It's just doesn't have patience with poor recordings. I do have a tube pre so will try that (hard to switch in and out though) . . . and I'm, as they say, "all in" with the vinyl so maybe a better cartridge is an opportunity.
So to follow up on Doggiehowser's suggestion, I'd need an equalizer with a built-in DAC. A quick look around last night showed a few but, as I think Unsound suggested, they are a bit pricey for my initial experimenting.
On the other hand, doing something in the digital domain exclusively as Kacz suggests is kinda exciting. (I'm a photographer and scratch built my last couple editing workstations so I kinda know my way around the bits and pieces). I just didn't realized that I could get a signal in and out of a computer without really trashing it. But this afternoon, searching some more, I realized that that's how all those guys that produce this stuff we love (i.e. music) are working in the digital domain. Jeez, suddenly there's also the possibility of converting some of my cherished vinyl. Never occurred to me to head that way. Card recommendations?
On the headphone question (thanks Unsound, Mapman & Geoffkait), I have Sennheiser 580s but as you say, the experience is really different. However, maybe getting into the digital domain could let me play with the crossfeeding technique? Never thought of using them to take the room out the equation...thanks.
Oh yes, room treatments will have to wait, my significant other is building another room on the house (she does this sort of thing regularly) so once it's clear I still have a listening space, I my have at it.
Thanks everyone!