40-50w tube amp for Aerial 9

I heard the new Dehavilland 50a at RMAF and just loved it. Dehavilland says it is nominally 40w, but practically closer to 50. I have concerns that it will not have enough power for my Aerial 9s (which I also love). They are 90db sensitive (pretty good) and have an impedance of 4 nominally, 3.2 minimum, low resistance (while I know the impedance is a factor, I am not sure how to apply it in this context).

Anyway, has anyone powered their 9s with this amp or a similar relatively low power tube amp? Anyone have any other thoughts on compatibility.

Thanks much.
Based on what I heard at RMAF with the 50A driving the Wilson Benesch Curve loudspeakers (88dB, 6 ohm nominal, 4 ohm minimum), I would think using the 4 ohm outputs on the 50A would work with your 90dB, 4 ohm nominal loudspeakers.

However, I wouldn't buy the amp without being able to hear it with your speakers. It's too expensive a proposition to take a flyer, IMO.
Thanks Tvad, you always understand the compatability issues that I do not. And, yes, I will definitely demo in my system. There is a dealer nearby. I just wanted to determine whether it was a waste of time before the demo.

BTW, what did you think of the 50a? Anything with a similar sound that you think I should also check out?
I thought the sound in the room was very good. Non-fatiguing, yet detailed, extended and balanced.

Never having heard the components or speakers before, it's impossible for me to comment separately on the electronics and speakers.
I have a basic understanding of how to impedance match a pre and power amp. I do not really understand how impedance works with speakers. Doesn't the power increase with higher impedance? (i.e. amps are often speced as x watts in 4ohms, 2x watts in 8ohms). If that is right, wouldn't the 6ohm impedance for the Wilson-B be a better match for the DH than my 4ohm Aerials. If you wouldn't mind, I would love a brief explanation. Thanks a lot.
Higher impedance (and a flat impedance curve) is better for tube amps, so, yes
the W-B speakers are a better match than the Aerials, IMO.

The question is whether Aerial designs their speakers with the Voltage Paradigm
or with the Power Paradigm. I don't know the answer to that question, but I
suspect it's the Voltage Paradigm.

This link explains the Voltage/Power Paradigms.
The 10t sounded best with tube amps under 100W/ch.The VAC 90/90 and Ren 70 drove them nicely.I would think that as you match the impedance tap to the speaker impedance,that you will get maximum power delivery.I believe that 40-50W should drive a 90db efficient speaker to reasonable levels,unless you need to "turn up" the volume to sustain a perceived level of detailing or control.
Something that you might like to research, its been talked about quite a bit here as Tvad knows, is the affect of the output impedence of the amp which is not linear thru its frequency response, especially if it is a tube amp many of which have a significant rise in the bass. The output impedence of an amp is not flat accross the spectrum, just as the impedence curve of the speakers is not flat. It helps to know, especially when matching speakers and amps on paper, where the rise in the amps output impedence would correspond with rises or fall in the speakers impedence curve.

Just something to do when your bored. Actually understanding it might even help you when considering the acquisition of new stuff. :-)
There are several tube amps like VAC, Manley or McIntosh that will work well with low impedance speakers. As to Dehaviland I have no experience and suggest you call the manufacture. To see if a tube amp would work with the Aerial 9 speaker you would need to know the impedance of the speaker over the entire frequency range. Tube amps work best with high impedance speakers or speakers that have a fairly flat impedance. The impedance of a speaker varys over the frequency range and a tube amp with higher output impedance than a solid state amp exagerates the variance making the speaker sound uneven. You can look at an article at Transendent Sound on Amplifier Output Impedance Why Its Important to better understand the dynamics.

I have been using a VAC PA90 with Thiel CS1.5 speakers that go as low as 3 ohms and have a fairly flat frequency response with a sensitivity of 86db. These amps are about 45 watts triode and 90 watts ultralinear. If you check Manleys website their amps are designed for an 5 ohm impedance.
Shredder- for some ss amps, its the other way around.
x watts @ 8 ohms
2x watts 2 4 ohms
Its called doubling down. some ss amps can, as far as I know, most tube amps do not do this.

For a speaker designed for voltage paradigm, no big deal. For a speaker that needs high current, its more important.
Vary helpful, thanks much.

Sorry for having more questions, but I am still learning. Anyway, how can you determine how the rise and fall of impedance for an amp correspond with rise and fall for a speake speaker?
Shredder, I don't think the amps impedance changes. You would need to look at the impedance graph for your specific speaker. Maybe you can contact Aerial for help, they also might make a recommendation. Or you can contact Dehavilland and tell them which speaker you are trying to use.