Hansen Prince & tubed amps

I've been considering changing to the Hansen Prince, but am concerned that my amps - Shindo Sinhonia - which are rated at 40 watts, may not have sufficient power for these speakers which are rated at only 87db. Does anyone have experience with these Hansens and tubed amplification of comparable power? thanks.
What is their impedance curve. If it is highish and stable 40 watts should give you sufficient volume. If they bounce down to 3 Ohms and lower you have cause for concern.
I have no personal experience with the Hansen Prince speaker but reading the specs 87dB and 6ohm nominal seems like borderline case with the Shindo. I pulled up the Stereophile review and in John Atkinson's measurements section, he measured the Prince's sensitivity at 85dB a little lower than Hansen's stated rating of 87dB, however, importantly the speaker does not got below 8ohms between 10-200Hz in the bass region so it will not present a difficult load in the bass region. It does dip below 4ohms in the mid-treble region and up (from about 2.5KHz and up)never going below 3 ohms it looks like. This suggests that with a tube amp, the high frequencies will be a bit of a tougher load on a partnering tube amp and may be somewhat attenuated. Here is the relevant section from John Atkinson's measurement section:

"My estimate of the Prince's voltage sensitivity on its tweeter axis was a little lower than specified, at 85dB(B)/2.83V/m. This speaker will definitely benefit from being driven by a powerful amplifier, particularly as its impedance (fig.1) drops below 4 ohms in the mid-treble and above. The impedance rises with decreasing frequency below 1kHz, which means that tube amplifiers, with their relatively high source impedance, will sound heavier in the bass than solid-state amplifiers with the Hansen. But as the Prince V2's impedance at lower frequencies doesn't drop below 8 ohms, this speaker should work well with tube amps."

Here is the impedance and phase angle graph across the frequency spectrum: http://www.stereophile.com/images/archivesart/408Hanfig1.jpg

My suggestion, take your Shindo Sinhonia amp with you to the local dealer who carries the Prince speakers (if you have someone locally) and try them out. You may get a sonic signature that you like but purely from the impedance graph it sounds like you may have attenuated high frequencies/treble and heightened bass response with tube amps, which may add up to a warmer than tonally neutral presentation.

As for the sensitivity (85dB-87dB vs. your 40wpc amp), if you are in an average-sized room and don't listen at crazy SPLs, you should be able to drive them adequately. But again, if you listen to a lot of rock and like to listen at concert levels than you are likely going to run out of steam with this pairing. Again, take your amps to a dealer and try them out. That will be the best way of determining their compatibility.

Hope this helps.
Great post! In this case it boils down to room size, listening level and music type. With these exceptional amps I`d give serious consideration to speakers without that high frequency dip below 4 ohms and with more efficiency to get the most from these Shindo amps.
Many thanks, Cmalak, for that very detailed and helpful answer. It is certainly make me think again about these speakers. The local dealer only has the Knight for auditioning, and this is similarly rated but I don’t know whether the impedance differs. But from what you’re saying, impedance is the critical factor.
My listening preferences are jazz, and classical and room size is 13 X 20, and I don’t listen at high levels, so I don’t think that is an issue.
My current speakers are the Ascendo MS, (rated @91db). These are normally used with ss or amps like the CAT – so lots of power. Having said that, the Sinhonias are coping with them, but at their limit. It seems from what you’ve said, by moving to the Hansens I might be going from the frying pan into the fire!! So I guess I should be looking at alternative speakers to the Princes.
Thanks also to Charles1dad.
Kegonsan...generally with mid-power tube amps like your Shindos, you want speakers that are fairly sensitive (90dB+) but more importantly speakers that do not present the partnering tube amp with a difficult load. Look for speakers that are nominally rated as an 8ohm impedance speaker with no dips below 6 ohms. Also the flatter the impedance curve the better as tube amps generally do not like big shifts in impedance across the frequency spectrum. Some speaker brands to think about - DeVore Fidelity, Coincident Technology, Audio Note, Audio Kinesis, and Merlin (plus many others but these come to mind).

Personally, I would seek out the Devore Silverback Reference speakers and audition them with your amp. I think you will like this combo very much. I admit I have not heard speakers from the other lines so I cannot comment on their sound other than to say they are typically tube-friendly and on paper should mate well with your amps.

Good luck.
Boy, Cmalak is on a roll with great suggestions(I own Coincident speakers they`re superb) that`s a very good list of tube friendly speakers. I`d also add Horning and Tonian Lab as potentially exceptional mates with the Shindo amps. I think all the above would match much better than the Hanson speakers i.e. much easier and relaxed load.
Once again, thanks guys for those added comments. Much appreciated. It's certainly given me a better understanding of what to be looking for when matching speakers and power, as well as some speaker products to explore.
Kegonsan...let us know what direction you go with. Would be interested to see how you make out.

Charles1dad...you have a great looking (and I am sure sounding) system.
Thanks for the kind comments.
Cmalak & Charles1dad, i will give you an update on what i finally decide.
Charles, I too had a look at your set-up, and it does look very sharp - especially those Speakers!
cheers for now.
It really depends on what music you like, how loud you want to listen and your room size.

But generally speaking 40W are definitely not enough for this speaker.

It happens to know very well the Hansen Prince V2 since I own them and the Knight as well.

I suggest that you test the Shindos in your dealer's Knights.

Knights are more demanding than Prince V2.

I've heard Princes with Viva Solista mk2 with 24 single-ended watts and the match was fantastic, but needed a bit more power for loud passages in orchestras.

Anyway try with the Knights and if you like it I reassure you that with Princes it will be easier.

Thanks for your comments. It was really helpful to have that feedback with your experience from both Hansen speakers.

I'll certainly try out my amps on the Knights.

I have Emperor in my room 10.5 x 17ft, I thought is going to overload but at moderate level of Aesthetix calypso at 46 setting was beautiful, calypso calibrated at 0db. Using krell FPB600, Aesthetix io sgn. Mk2 with 1PS. VPI classic TT/dyna XX2mk2. Loading at 2.15gm and 1k ohms.
Hansen is a beautiful speakers, I just got it yesterday ,