Amp's nominal power rating - any use?

Magfan, the phase angle discussion you're trying to have is frequency-dependent, which you've ignored, so "next to nothing" still seems a stretch to me, which was my point. Since most listening, even on the OP's speakers, will be done with the first few watts, the effective frequency response will be the most important determinator of the sound.

I have no idea what Kijanki is talking about, with his percentages.

Your speakers are good for about 87db for 1 watt into 8 ohms (at one meter). This means an amp that clips at 8 watts will drive the speaker to 96db at one meter, which most people will consider quite loud. I would suspect a lot of people don't really listen to speakers this small any louder than that.

The 30 watt amp will be able to drive the speakers 6db louder, all things being equal, and they probably aren't. 6db is pretty significant, but since the 6db is 6db over 96db, you may not notice it, depending on the music you're playing, the size of your room, and your average listening level.

Since these are single-ended amps you're talking about, they will have a sonic signature, and the transfer function differences between the amps just may overwhelm the power differences.

Have you ever connected your speakers (which are pretty good for speakers of that size) to a decent solid state amp of, say, 100w/ch, just for grins?

Kijanki, it is difficult to disagree that music has varying loudness, but 45.9%? I don't think your calculation is nearly accurate enough to claim a number with such precision. For one thing, the dynamic range of music varies so much by music type and recording, though I suppose someone with a SET and minimonitors is unlikely to be listening to Kayne West.

Regardless, I'm still not bought into the efficacy of your calculation.

As for Magfan's comments about adding capacitance or inductance into the power calculation, "next to nothing" seems like a big exaggeration. But considering we're talking about a tube SET here, which is going to be the most sensitive design to load variance, amp and speaker matching is of more importance than usual, I'll agree. Once you're in SET territory, I think the only practical way to tell if an amp is compatible with a speaker is to listen. No one publishes enough specs to make a worthwhile prediction, and even if they did, very few of us could probably do a reasoanble interpretation.

Dongiovanni, I confess to being biased against SET amps. I think most people that like them are just hearing a modified frequency response caused by the electrical anomalies of the output stage, like a high output impedance. Frankly, considering the high quality of your speakers, I think it might be very interesting if you try a solid-state amp and tell us what you think. If the receiver is good enough (they do okay above approximately the $500 price point) you will at least get a first impression, though the speakers are good enough a better amp might have an audible difference. If you still think the SET amp sounds a lot better, I respect that. Choosing a system is personal decision.