crossover newb with passive subwoofer questions


I am considering purchasing a stand alone crossover for my system.
My system is comprised of the following, source to speakers:
MacMini to DAC to tube line preamp to tube amplifier to *passive* subwoofers (one per channel) with monitor satellites wired off their respective channel subwoofer.
The crossover devices that I've seen all seem to have RCA outputs (rather than speaker outs) which would imply to me that that the subwoofer and satellites would need their own amplifier.
Is there a device, or way to avoid the need for another amplifier,using a crossover "seperate" with my passive subwoofer/satellite setup? I'm assuming that such an animal would allow for wiring the speakers for each channel in more of a parallel arrangement, as opposed to a series arrangement as I have them now....
rabco
I've used the Parts-Express plate-amps and they are a reasonably priced fix.They are mono units.Since you are using two subs-two are required.
Onkyo for subs:You will need a crossover.Maybe a Dahlquist LP-1 or the NHT X-1.The LP-1 is passive (capacitor) on top and active on the bottom.If you have two outputs on your pre,you might run the monitors full-range and use the LP-1s' bottom (variable freq/gain) to control/balance the subs.This will allow you to adjust the subs and not introduce more circuitry into the monitors.
Tpsonic, thanks for the suggestions.
My preamp is a simple tube line preamp with only one output. I suppose "Y'ing" the output with RCA lines, to what would be two separate amps would be a no-no for several different reasons....
Rabco-

Have you looked at these products at all? Many provide for an RCA input, a high-passed RCA output for the main channel speaker amp and, of course, internal routing to the subwoofer of the low-passed signals. No Y-connector is needed.

Kal
Kal, just covering all my bases with questions that address all my potential solutions.
For example, if I use my ss Onkyo as a subwoofer amp, I may need 2 pre outputs to drive the subwoofer amp and the tube amp that would drive the Legacy monitors.
I understood that some of the units in the links you provided are as you describe. Which may make them the most attractive way to proceed.
Just trying to sweat the details. These are devices I've only seen pictures of, & I haven't deployed.
Frankly, if you use the Onkyo, you will still be faced with the problem that you lack proper crossovers. Y-connectors are a non-issue; use 'em if you need 'em.

Kal