Spec sheet says 20W Nom - I've run them with an Onkyo 7.1 receiver with "rated" power of 135Wpc, but when de-rated for actual real world conditions with more than just 2 channels, let's call it "maybe 100 with a stiff tail wind" . Even so, it was more than enough for my listening needs, and if your Yamaha has anywhere near the same flexibility in its speaker set-up/ bass management, you should be able to safely configure it to eliminate the bottom couple of octaves where risk of damage from over-driving is the highest. I had set mine as "small" and with XO to the LFE channel higher than the THX standard of 80Hz.
Anyway I set my speakers to large because I made these for listening music too and I thought them to cut to 60 hz, but because setting them to large the receiver let whole bass to them, for music I use channel mixer in foobar for bass management. I put my system to 5.1 despite I listen music only stereo. I tried with them on small. I didn't' especially like they sound at 60 hz as this was my target crossover point (with small setting). For music I find 80 hz ruined to much of the bass stereo effect. Generally I don't like to listen too loud. I'm for clarity and details, in this case alpairs 7 are brilliant. My asking was where I should go at max with the volume. I set it now at -32db. Anyway my speakers are new and I will not raise the volume level till 100 hours break-in.
I have run full range speakers on a 100 watt per channel Odyssey Audio Khartago with no problems and excellent results. I have run these same speakers on a TPA3118 SMSL SA-36A pro, (24 volts). This little amplifier sounds pleasant enough but fails to drive these speakers properly. Even though full range drivers are fairly efficient, driving them with tiny amplifiers is a big mistake. For people on a tight budget, look at the Emotiva a-100 mini. I also own this amplifier and this one works. The TPA-3116 class amplifiers are interesting but disappointing.
What you want is an amp with sufficient power that it never clips at the loudest volume you will ever listen at. I have ~50w/ch (advertised 80) class D on my A7.3's. I have 750w/ch on the 12" sealed subs (FAST layout). Looking for 100dB peaks/70dB average at 2.5m.
What do I look for in an amplifier? I listen to a lot of acoustic jazz. I like to test amplifiers with late 50s to early 60s stereophonic recordings. Listen to the kick drums. Does it sound like a drum or a recording of a drum? Another thing to test is the volume control. An excellent amplifier will sound great at any reasonable volume. If you are constantly twisting the volume control to find that sweet spot, you have serious amplifier issues. I have 3 class AB amplifiers that easily pass the test and 3 class D amps I find disappointing. I am not saying that all class D amplifiers are bad but I am getting skeptical.
To understand why small class D amps sound bad when driven hard, you need to look and the power vs distortion curve. Distortion goes down with increased power to a point. Then the distortion curve goes practically straight up. The published power rating is usually at 10% distortion and represents pretty close to the ultimate power at any distortion level. Once you figure in what kind of headroom you need, say 20dB, you see that a 10w/ch (rated) class D amp just won't cut it.