N-set, I have seen a guy at DIYAudio who built an amp around GU-48. I sent his meals but he did not replay. I have seen a few (very view) people in Russia spoke about GU-48 and some of them built something. I do not know what result is.
It is very difficult to get from people who build such amps any feeling about sound. To build the thing is a complex possess that require a lot of knowledge and pretty much years of experience. People got so infatuated with overcoming technical difficulties during construction of the amp that they are losing eyes from the ball and the all purpose of the build stop to be on their aim.
I am sure no one that I heard off made bass DSET around GU-48. The guys who use this tube would try to get the most from the efforts and would go wide range. This is understandable. Moreover, the people who need 150+ Watts of wide-ranges amplification would be hardly the people who use high quality acoustic systems. So, what they think about own amp is kind of irrelevant to me.
The whole project like this in a way an applied waste. It will cost a lot or money, it will cost n-years of time and in the end it will answer very little questions. In fact the questions that the amp will answer will be so narrow that only insane man would do for it. Still, I would be the one who would feel that SOMEONE has to do it. Sure it will be not me, thankfully.
N-set, if you are planning to do something like this then you have to have good reasons to do it, not just a fact the you can do it. BTW, there is an alternative about which I have been thinking. There was in 50s a class of magnetic amplifiers, there very stable and very high power.
They work well only at LF and this is what I would like to be with this DSET…. I just need to find an old man who still remembers them. I think it might be a good candidate to try for ULF.The Cat
"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche