Anyone Bi-amping with tube high & solid state lows

Gain controll isn't a bottom line here.
The gain should be controlled dynamically unless the amps at the top and bottom end have absolutely identical characteristics.
To controll gain dynamically you need an active crossover and remove built-in speaker crossover.

I think you would need arround 8 watts plus so 12 would work great .hope this helps I tried much gear to get a great match .JK

I am biamping my MG 3.5s with a Marchand 126s (Balanced I/O) active x-over. I am using ARC VT100 MKII for the treble/midrange and Kenwood L07 monoblocks for the bass panels. The results are incredible. Careful selection of output levels and x-over points and slope are required for seamless blending. In order to faclitate blending of the amps, I used a 6dB/octave @ 250 Hz slope for the high pass, whereas for the low pass I used a steeper slope, 18 dB/octave at 200Hz. In general, I would recommend a gradual slope for the high pass section and a steeper slope for the low pass (assuming that the solid state amp is driving the bass of your speaker).

My experience has been that I can use different amps to bi-amp as long as I keep the x-over under 200 HZ as in an upper bass or sub-woofer application. Much above that frequency and the differences between the amps becomes apparent as I approach the midrange leading to a discontinuity in the sound.

Jeff

Your post above specifies the need to controll gain dynamically. Can you clarify what that means? As I understand it, an amplifier has a fixed nominal gain. It is nominal because there is some reactivity to complex loads. So the gain may at a particular frequency may be a product of the impedance at that frequency. But the overall gain characteristic is fixed (unless of course there are level controls on the amp). Therefore, I don't get what "dynamic control" means. Is the idea that the active cross-over adjusts filtering in real time based on the level of the input signal? What is dynamic about the filter? I thought the only distinction for active cross-overs was that each speaker element is driven by one and only one amplifier, unlike passive bi-amping.