bi-amp with a tube amp and SS

Is there any body who experieced biamping with a tube amp for low frq. and SS for high freq.

I think same power (watt) is not a must, is that true?
The amps power matching is not a must, but you should try to match the amps input sensitivity and overall gain if possible. If not possible, you could buy a pair of in-line attenuators to adjust the signal so that you get equal volume from both amps.

I do it and love it. You have to be able to modify the gain on one of the amps so you can match their output levels. Power output doesn't factor in - only the input sensitivity does (gain will be fixed once set). If you can find two amps with the same sensitivity, you are in luck since you then won't need gain control. You also would need a preamp with two sets of outputs.

I would try a SS pro amp with gain control on the bottom end, and let the tube amp do the the mids and highs, as that is where most of the "magic" of tubes will be realized.
Pre-amp w/ 2 outputs OR a Y cable. They can be custom made with one RCA male on the upstream end, 2 on the downstream end, as long as you need, by most cable-makers.
Oh - I just realized you said tubes on the LOW freq! That does not make sense to me. Put the tubes on the highs and keep the high-damping-factor SS amp for the lows. Much more logical that way.

tube on the top/ss on the bottom!!!!!
Yes thanks. I made a mistake while writing. U understood what I ment.
What if I use mono tubes for uppers and stereo SS for lows do I need to mach sensitivities again or what?
If the sensitivities aren't matched, which they most likely will not be, you can just buy a pair of in-line attenuators like EVS to match them externally. You would only need one pair, placed on the more sensitive amp(s).

Like these.