Stereo pre-amps with dual outs for bi-amping and a subwoofer line out

If you like tubes the PrimaLuna Dialogue Premium has extra pre -outs. I have a couple of subs hooked up this way but used to use an audioquest splitter on my last preamp with the same results. 

If the outputs are just jumpered at the preamp is there really any reason to bi amp. I can see it in a fully active system with external crossovers. I had a 3 amp Linn System like that and heard the difference. I can never really  say I have heard a difference with bi amping. Put the money into one better amp. 

Emotiva XSP-1 preamp has four outputs

All four can be set to full range or two can be set to high pass 50 to 250 hz and two can be set to low pass 50 to 250 hz

I agree with pkvintage. I currently triamp in an active stereo system and definitely hear the difference. I have removed the passive crossovers in my speakers.

In the past, with same speakers and tube amp I now use for midrange/tweeter, I tried biamping out of the preamp as you suggest, with a large ss amp for bass. Didn't like it at all.

BTW, in a setup as you describe all amps reproduce the full bandwidth, so not a good solution. In this case a bigger amp is generally better.