Well the reality is that if the chosen speakers have high efficiency many tube amps perform just fine. My amp also uses the GM-70 as a DHT SET.
I just feel strongly that the time is ripe to consider such efficient speakers with the use of a properly matched tube amp and tube preamp. There has been strong enough sentiment here to warrant such. Otherwise the thread is nothing more than a laundry list
I have to say that I only partially agree Steve.
Yes there should be a tube system alternative to the solid state for the new project by Jeff as this covers a different preference and is not seen as being a group test comparison test (which doing sources would had).
Furthermore it evolves the project's process by including and then providing a narrative that it is possible for two different SOTA to coexist even if they sound subtly different, the limitation as discussed is that it is focused specifically on the preamp-amp as other changes start to become too much for such a project.
Where I disagree is that the tube products selected being SOTA must be able to play on the majority of SOTA speakers, and all those selected for the short list.
Surely a part of SOTA is the product being more universal in that it does not restrict a listener to specific set of hardware (such as horns-very sensitive speakers-etc), the leeway though should be to ignore very poor sensitivity speakers.
Now this may be a challenge for sets (definitely for most) but there may be some that are still acceptable such as your Lamms, while other tubes will comfortably fit such as my suggestion of the 60th anniversary McIntosh that has good amount of watts, very low distortion and frequency response variations across whole frequency and various impedance, and output impedance matching very good SS amps.
Bearing in mind that this is a project that is as much an adventure of experience including setup and listening (and for me this is what makes it superb) as it is about the final setup chosen, then we have to accept the possibility that out of this may come an acknowledgement that there is not enough watts for final critical listening - or possibly that a product like Steve's Lamms do have enough.
It is not possible to state until the time they are part of the process, which I guess means that the project may need to define an earlier pre listening test to have an indication of such performance for the tube amp.
The alternative is to have a short list of several amps including those with experience have shown can work with average sensitivity speakers such as the Lamm while also having more powerful tube amps and then take off the list if they fail at time of choosing the specific whats best setup in the room.
Anyway to me this is not a problem, just part of the experience and enjoyment of this project.
Just to add about SOTA and the product being universal, this also works the other way with horn speakers (if considered) in that they should sound excellent with the SOTA SS pre-power amps on the short list, and not restricted to tube products even if it means part of the sensitivity becomes meaningless with some of the more powerful SS amps in the list.
Thanks
Orb