I understand one way to tackle the issue of using SET amps is with high sensitivity speakers. Is there a 300B or something that gives you that same sound out there with power so you have more speaker options?
@audiovicker You have put your finger on the classic issue with tube power. Its expensive and difficult to get right. If you look back to the 1950s before the transistor, you'll see that high efficiency speakers like Altec, JBL, Klipsch and EV were common.
If you really want to hear what your amp is about, in most rooms speakers with efficiency north of 100dB is what you need. My speakers are 98dB but running a 300b amplifier on them will not show off what the 300b does. You really do need that kind of efficiency! This is because if you really want to know what the amp does, it should never be asked to make more than about 20-25% of its rated power! Otherwise distortion colors its presentation too much.
If that's not an option you'll need more power. That likely means a push pull amplifier, since 8 Watts or so is really the upper power limit of SETs where they can be considered 'hifi' in terms of bandwidth. SET's single biggest Achilles Heel is bandwidth and power- above 8 Watts bandwidth suffers so much that if you have a speaker that is truly full range, you'll notice that there's a problem!