Which high power SET

Edoit,
Atmasphere makes a good point and his reasoning is sound. However if there's any chance you can hear one of those premium SET amplifiers with the speaker, please do so. From personal experience I can say that expectations aren't always reality. Those are "very good" SETs on your wish list. Depending on your taste, music genre,room size and listening volume they could be just what you want.Compare them to a higher powered(pentode tubed) push pull amp and decide. You may be pleasantly surprised by what you hear.DHT tubes are capable of producing beautiful natural sound.
Good Luck,
Charles,

I'm using a push pull 30W and it's more than enough for my listening tastes. Hence the thought of SET for more refinement. To rephrase my question, which of the 3 on the list would be the best match for shindo masseto pre amp?

I doubt that there are many here, or for that matter anywhere, who have heard your particular combination of gear with the three candidate amps. I have only heard the WAVAC and the system sounded quite good so it is a possible choice.

I own a low-powered SET amp (parallel 2a3) as well as a pushpull triode amp (45 tube) and a pushpull pentode amp (349 tube). All of these amps sound different and quite good. I don't think one should be completely committed to one particular approach as being inherently better than another. At this time, the pushpull pentode amp is in my system because it delivers the most realistic sounding midrange and punchier bass (though not as nuanced bass as the parallel 2a3). In other words, if you are looking for something better than your 30 watt pushpull amp, candidates for "better" may be another pushpull amp from a different designer or one using a different tube or design implementation. I would personally be wide open to trying different options and I would insist on hearing these options in my particular system.

I have heard 211 and 845 SET amps in various systems and they can be very good sounding. But, at least when run in extremely efficient systems, these amps don't deliver quite the same sound as a 45 or 2a3 SET (the amps I generally prefer). I suspect that every choice has certain tradeoffs and one must listen and decide which tradeoffs to make.

I think that where some power is really required, but not extremely high power, OTL amps should be in consideration. These amps are amazing when it comes to perking up the sound--they are fast, dynamic and have oodles of "presence" without being overly harsh and unpleasant. Some may not exactly fit into the category of being "refined" sounding, but, you may change your priorities once you hear them. Like any kind of topology, diffent implementations are voiced differently so you would have to hear the different choices. I happen to like some lower-powered SET amps because they can deliver a lot of the same kind of lively sound of OTLs (taking into account there MUCH lower output), but one really must have ultra efficient speakers.

Larryi,
Many good points you've made as usual. I agree that no single amplifier or particular topology is perfect, they all will require some degree of compromise. The key to ultimate success and long term happiness is knowing what type of sound/presentation you truly want. I stuck with the SETs since this is what Edoit expressed interest in. I believe that he's headed in a very good direction with his list of candidates.

Edoit you say that you current 30 watt amplifier is enough power and pleases you, that's important information to know. Based on that I'd strongly urge you to listen to the 845 SETs you're curious about. Given your comments it suggests that high quality 30 watts is satisfactory with your speakers. Quality will often win out over quantity with the appropriate speaker match. As Larry said an OTL is a viable option (they all sound different depending on the brand).Personally high quality SET amplifiers are the closest I've heard to mimicking the live venue experience. That's why I'm very supportive of your pursuit of them. Naturally YMMV.
Best regards,
Charles,

Edoit, I think you will find its in your best interests to do an audition on your speakers in your home if you can.

SETs with the same power as your 30-watt push-pull amp may not come off as just as refined. I alluded to the issue, but here it is in plain black and white:

If you want to really experience what an SET does, the efficiency of your speaker should be such that the amp *never* is asked to make more than about 20-25% of full power. If you follow this rule you will get the most bang for the buck out of your SET investment dollar. The reason has to do with how SETs make distortion- above that power level the higher order (harsher) distortion elements come into play. As the power demands are decreased, the distortion goes to unmeasurable and is the reason for the 'inner detail' claims you see describing a lot of SETs. This has to do with how distortion can mask detail per the ear's masking rule.

Since this speaker also has some bandwidth, you may also notice that an SET of similar power simply does not have the bass delivery, as it is very difficult to make an output transformer that can deliver bass and full treble extension at that power level.

I'm not a fan of pentode amps FWIW, being a manufacturer of triode amps myself :)

I think you have sussed out that SETs have a following for good reasons- I think if you look into it, you will find that the most successful systems have lower powered SETs (which have more bandwidth) and much more efficient loudspeakers. My speakers are 98 db 1 watt/1 meter, and I find that 30 watts is a minimum in my room, which is an average size. I do have a type 45-based amplifier (push-pull, makes about 6 watts) and it sounds better than the 45 in SET mode on the same speaker; but even so its hardly enough power to do the job!

Now for the math: the 6 watts that I have on my speaker translates to the same sound pressure level on your speaker with about 120 watts. Think about that. There is no point to buying any amplifier and then pushing it as hard as you can.