I recently purchased a Terra Engineering Star 10. It uses el34, kt88, or 6550 tubes. It puts out ten watts and has a volume control. I have to admit, this little monster can bring across low level detail like I've never heard before. I generally prefer my ARC vt100/bat vk-5i setup, but there are parts of a recording that only the SET amp can bring accross.
I have it hooked up to my mcintosh mr71 tube tuner and a set of (believe it or not) Gallo Nucleas Micro's. The micros are 92db efficient. There is not a lot of weight behind the instruments, so you seem to be listening to a very detailed, delicate 'sonic image' of the instruments that is 'floating' in the soundstage. Some of this is a characteristic of the Gallo's, but I hear a similar effect when I hook the underpowered terra to my audio physic avanti's, or my Spica TC-60's.
Like tax rules, there is a surrealistic quality to them. It's not quite reality, but some aspects come across more perfectly than any amp I've heard. Bass guitar for example does not sound real at all - it's very distant, weak, and shallow sounding, but you hear the fingering more. Violins, Trumpet and the upper register of a piano sound more detailed and intricately textured than I've ever heard. The plink is just right.
Vocals are affected similarly. You hear more delicate inflections, but some information is also lost. Jesse Norman does not come accross as being ten times more powerful than Chet Baker, yet you hear Chet's sad ass, no smiles for miles wimpering more distinctly than ever before.
I played trumpet 20 years ago. I realized when listening to the set amp that I could hear the air rushing through and resonating with the instrument's brass. Blow into a plastic diet coke bottle (you know, the whislin sound), then image a 100 Watt ARC tube amp trying to replicate that sound. The arc amp can't do it, the SET amp can.
