I am using a tube VAC Avatar Super Integrated as my preamp with a BRYSTON 9B-ST power amplifier of 5 channels. I am bi-amping a pair of Magneplanar 1.6 QR. One amp for the highs and the other for the lows. So i am using 4 of the channels into 4 ohms speakers. At 200 watts per amp, in total 400 watts per channel into 4 ohms the speakers are swinging, jumping and making incredible reproduction of all types of music. After using the speakers alone for months where the bass reproduction had been very good, for Maggie's, I connected 2 REL T-5 sub-woofers, 1 to each channel and the music reproduction got even better, obviously the bass reproduction became outstanding. Tube preamp and SS amp., works for me.
I have a second system. A ROGUE tube pre-amp with Exposure mono blocks amplifying a set of System Audio 2K speakers.