Switching to solid state amp?

It is not the point of warm or not warm sound, the point is to achieve harmonically correct and balanced sound. For $10k I would probably get Atma-Sphere preamp with phono and amp. Yes, all tubes. Unless you can jump to Nagra, FM Acoustics, Gryphon, Ypsilon hybrids etc. But even then very careful audition and match with speakers would be in order.

Octave has an excellent reputation, including their integrateds.
As I understand it, and I might be wrong, Gryphon Diablo 120 is not quite Diablo 300 only less powerful. The latter is a reference level integrated. You would want to listen to them both if you considered Gryphon. The phono stage, $2200 option in either, should be excellent. Diablo 120 is $11k and Diablo 300 is $16k, without phono or dac. This would no doubt be different sound - Octave and Gryphon top integrateds.

david_ten, this is just my tentative assumption, not based on any experience or science but only on my impression in differences between the designer's presentation of both. Flemming Rasmussen obviously likes his Diablo 300 and considers it his achievement in the designing of an integrated amp. Diablo 120 presentation sounded like - it is an excellent integrated, better than previous generation Atilla, but..
However, this is my impression and speculation, that's all.

Russians have been making great tubes for ages. They still do. There are also excellent Chinese tubes.
As for the future of tube equipment, I don't know. It might be doomed, it might be not. There are enough good tubes for our lifetime, though, just will be getting more expensive, perhaps.

In addition, Diablo 300 DAC option is much more expensive, and you can have both phono stage and DAC in it, Diablo 120 is either/or only.