Generally speaking, its a tough question you ask, but its good that you realize the problem is the preamp. Its probably the hardest component to get right. The only preamp I've owned that you have is the PCA-2. I wasn't impressed with it. It had a very polite sound but just didn't inspire in any way. I can't say for sure, but I'm pretty certain you would like a Conrad Johnson Premier 16 if you can find one. I had mine next to the PCA-2 and it just beat it in every aspect. Given your description, I think its exactly what you are looking for.
As far as tubes go, you need to be careful. You can easily get one that is not to your liking. The sound of tube preamps vary just like every other component. Again, given your description, I think you may like something from Sonic Frontiers or an entry level BAT (used).
One last option I would recommend you look at is a good passive line stage. How well a passive works can vary greatly so I think a demo would be mandatory.
If you don't have a way to demo anything, I would try to buy something used for a good price. If you end up not liking it, you should be able to sell it for close to what you paid. Its a good way to go if you don't have any other options.
There's a lot of great equipment out there other than what I list. I'm sure some of the other members will give you some solid recommendations, as well.
As far as tubes go, you need to be careful. You can easily get one that is not to your liking. The sound of tube preamps vary just like every other component. Again, given your description, I think you may like something from Sonic Frontiers or an entry level BAT (used).
One last option I would recommend you look at is a good passive line stage. How well a passive works can vary greatly so I think a demo would be mandatory.
If you don't have a way to demo anything, I would try to buy something used for a good price. If you end up not liking it, you should be able to sell it for close to what you paid. Its a good way to go if you don't have any other options.
There's a lot of great equipment out there other than what I list. I'm sure some of the other members will give you some solid recommendations, as well.