Preamp suggestions 1200$ used

Try the Marsh P2000. You can get it new at your price point. It has all the qualities your list.

geoff,
i drove tyler linbrooks with a rogue 88 (stock) and 99 magnum combo for about a year without the slightest complaint whatsoever, very nice. out of curiosity one fine saturday i wanted to see how the cary sli-80 integrated would perform at home with my tylers and front-end. i was very impressed to say the least. simple, musical and involving, i was thinking music, not hi-fi the entire time, cd after cd after cd...i do not use a sub myself, but the sli-80 does have a sub out which would suit your needs. from what i've read the sli-80 takes another leap forward with some tube swapping, something else to think about.

life and this hobby being what they are, of course i ended up purchasing a cary v12 privately and still use my 99 magnum pre, but if i wanted one less box, the sli-80 integrated would definitley be on my list. i understand this suggestion would make your rogue 88 irrelevant, but i'd say consider this now rather than later,if you are in no rush to buy.
otherwise, you could hardly go wrong picking up a matching rogue preamp. mark at rogue is a stand-up guy and a pleasure to do business with. great amps and great customer support.
great choice in speaker
hope this helps you decide
cheers

Thought I'd add that this preamp will function in a strictly 2 channel audio system.

I keep seeing "line level stage" in some of the explanations of the preamps, my understanding was line level was just another term for RCA any help here?

You can get a used Sonic Frontier Line 1 for about $1000.
It's one of the better hi-end tube preamp around.
built like a tank with hi quality components, 2sets of outputs,remote: volume, balance, phase, mute, inputs, stby has bypass sw for SSP, and more...

Just check out the WWW.. for Sonic Frontiers line series preamps and read the reviews...Happy hunting. Even though Sonic Frontiers no longer manufacture these product, they still provide customer support (repairs & upgrades).

Happy hunting and good luck. Hope this helps.

I thought that with the CL15 you did not need a preamp. Why don't you give that a try and use the volume control of the CL15